diff --git a/benchmarks_test.go b/benchmarks_test.go
index ea676771..c989792a 100644
--- a/benchmarks_test.go
+++ b/benchmarks_test.go
@@ -18,8 +18,8 @@ import (
 	protocol "github.com/libp2p/go-libp2p-core/protocol"
 
 	"github.com/ipfs/go-bitswap"
-	testinstance "github.com/ipfs/go-bitswap/client/testinstance"
 	bsnet "github.com/ipfs/go-bitswap/network"
+	testinstance "github.com/ipfs/go-bitswap/testinstance"
 	tn "github.com/ipfs/go-bitswap/testnet"
 	cid "github.com/ipfs/go-cid"
 	delay "github.com/ipfs/go-ipfs-delay"
diff --git a/polyfill.go b/bitswap.go
similarity index 90%
rename from polyfill.go
rename to bitswap.go
index 95dcd5dc..f6fdb4cb 100644
--- a/polyfill.go
+++ b/bitswap.go
@@ -5,8 +5,8 @@ import (
 	"fmt"
 
 	"github.com/ipfs/go-bitswap/client"
+	"github.com/ipfs/go-bitswap/internal/defaults"
 	"github.com/ipfs/go-bitswap/message"
-	"github.com/ipfs/go-bitswap/metrics"
 	"github.com/ipfs/go-bitswap/network"
 	"github.com/ipfs/go-bitswap/server"
 	"github.com/ipfs/go-bitswap/tracer"
@@ -24,7 +24,7 @@ import (
 var log = logging.Logger("bitswap")
 
 // old interface we are targeting
-type old interface {
+type bitswap interface {
 	Close() error
 	GetBlock(ctx context.Context, k cid.Cid) (blocks.Block, error)
 	GetBlocks(ctx context.Context, keys []cid.Cid) (<-chan blocks.Block, error)
@@ -44,7 +44,8 @@ type old interface {
 }
 
 var _ exchange.SessionExchange = (*Bitswap)(nil)
-var _ old = (*Bitswap)(nil)
+var _ bitswap = (*Bitswap)(nil)
+var HasBlockBufferSize = defaults.HasBlockBufferSize
 
 type Bitswap struct {
 	*client.Client
@@ -81,9 +82,12 @@ func New(ctx context.Context, net network.BitSwapNetwork, bstore blockstore.Bloc
 		serverOptions = append(serverOptions, server.WithTracer(tracer))
 	}
 
-	stats := metrics.New(ctx)
-	bs.Server = server.New(ctx, net, bstore, stats, serverOptions...)
-	bs.Client = client.New(ctx, net, bstore, stats, append(clientOptions, client.WithBlockReceivedNotifier(bs.Server))...)
+	if HasBlockBufferSize != defaults.HasBlockBufferSize {
+		serverOptions = append(serverOptions, server.HasBlockBufferSize(HasBlockBufferSize))
+	}
+
+	bs.Server = server.New(ctx, net, bstore, serverOptions...)
+	bs.Client = client.New(ctx, net, bstore, append(clientOptions, client.WithBlockReceivedNotifier(bs.Server))...)
 	net.Start(bs) // use the polyfill receiver to log received errors and trace messages only once
 
 	return bs
diff --git a/bitswap_test.go b/bitswap_test.go
index 33603726..055a9030 100644
--- a/bitswap_test.go
+++ b/bitswap_test.go
@@ -10,9 +10,9 @@ import (
 	"time"
 
 	"github.com/ipfs/go-bitswap"
-	testinstance "github.com/ipfs/go-bitswap/client/testinstance"
 	bsmsg "github.com/ipfs/go-bitswap/message"
 	"github.com/ipfs/go-bitswap/server"
+	testinstance "github.com/ipfs/go-bitswap/testinstance"
 	tn "github.com/ipfs/go-bitswap/testnet"
 	blocks "github.com/ipfs/go-block-format"
 	cid "github.com/ipfs/go-cid"
diff --git a/client/bitswap_with_sessions_test.go b/client/bitswap_with_sessions_test.go
index 8ba2d6e9..5e4d2454 100644
--- a/client/bitswap_with_sessions_test.go
+++ b/client/bitswap_with_sessions_test.go
@@ -8,7 +8,7 @@ import (
 
 	"github.com/ipfs/go-bitswap"
 	"github.com/ipfs/go-bitswap/client/internal/session"
-	testinstance "github.com/ipfs/go-bitswap/client/testinstance"
+	testinstance "github.com/ipfs/go-bitswap/testinstance"
 	tn "github.com/ipfs/go-bitswap/testnet"
 	blocks "github.com/ipfs/go-block-format"
 	cid "github.com/ipfs/go-cid"
diff --git a/client/client.go b/client/client.go
index 1380e0d9..3a208749 100644
--- a/client/client.go
+++ b/client/client.go
@@ -82,16 +82,14 @@ func WithBlockReceivedNotifier(brn BlockReceivedNotifier) Option {
 }
 
 type BlockReceivedNotifier interface {
-	// ReceivedBlocks notify the decision engine that a peer is well behaving
-	// and gave us usefull data, potentially increasing it's score and making us
+	// ReceivedBlocks notifies the decision engine that a peer is well-behaving
+	// and gave us useful data, potentially increasing its score and making us
 	// send them more data in exchange.
 	ReceivedBlocks(peer.ID, []blocks.Block)
 }
 
-// New initializes a BitSwap instance that communicates over the provided
-// BitSwapNetwork. This function registers the returned instance as the network
-// delegate. Runs until context is cancelled or bitswap.Close is called.
-func New(parent context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Blockstore, m *bmetrics.Metrics, options ...Option) *Client {
+// New initializes a Bitswap client that runs until client.Close is called.
+func New(parent context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Blockstore, options ...Option) *Client {
 	// important to use provided parent context (since it may include important
 	// loggable data). It's probably not a good idea to allow bitswap to be
 	// coupled to the concerns of the ipfs daemon in this way.
@@ -155,8 +153,8 @@ func New(parent context.Context, network bsnet.BitSwapNetwork, bstore blockstore
 		sim:                        sim,
 		notif:                      notif,
 		counters:                   new(counters),
-		dupMetric:                  m.DupHist(),
-		allMetric:                  m.AllHist(),
+		dupMetric:                  bmetrics.DupHist(),
+		allMetric:                  bmetrics.AllHist(),
 		provSearchDelay:            defaults.ProvSearchDelay,
 		rebroadcastDelay:           delay.Fixed(time.Minute),
 		simulateDontHavesOnTimeout: true,
diff --git a/decision/forward.go b/decision/forward.go
new file mode 100644
index 00000000..d19cda94
--- /dev/null
+++ b/decision/forward.go
@@ -0,0 +1,12 @@
+package decision
+
+import "github.com/ipfs/go-bitswap/server"
+
+type (
+	// DEPRECATED use server.Receipt instead
+	Receipt = server.Receipt
+	// DEPRECATED use server.ScoreLedger instead
+	ScoreLedger = server.ScoreLedger
+	// DEPRECATED use server.ScorePeerFunc instead
+	ScorePeerFunc = server.ScorePeerFunc
+)
diff --git a/forward.go b/forward.go
new file mode 100644
index 00000000..2beb7590
--- /dev/null
+++ b/forward.go
@@ -0,0 +1,17 @@
+package bitswap
+
+import (
+	"github.com/ipfs/go-bitswap/server"
+	"github.com/ipfs/go-bitswap/tracer"
+)
+
+type (
+	// DEPRECATED
+	PeerBlockRequestFilter = server.PeerBlockRequestFilter
+	// DEPRECATED
+	TaskComparator = server.TaskComparator
+	// DEPRECATED
+	TaskInfo = server.TaskInfo
+	// DEPRECATED
+	Tracer = tracer.Tracer
+)
diff --git a/internal/defaults/defaults.go b/internal/defaults/defaults.go
index 54a9eaa6..6f7c2e74 100644
--- a/internal/defaults/defaults.go
+++ b/internal/defaults/defaults.go
@@ -19,4 +19,9 @@ const (
 	BitswapMaxOutstandingBytesPerPeer = 1 << 20
 	// the number of bytes we attempt to make each outgoing bitswap message
 	BitswapEngineTargetMessageSize = 16 * 1024
+	// HasBlockBufferSize is the buffer size of the channel for new blocks
+	// that need to be provided. They should get pulled over by the
+	// provideCollector even before they are actually provided.
+	// TODO: Does this need to be this large givent that?
+	HasBlockBufferSize = 256
 )
diff --git a/metrics/gen.go b/metrics/gen.go
deleted file mode 100644
index 000a8cde..00000000
--- a/metrics/gen.go
+++ /dev/null
@@ -1,132 +0,0 @@
-package metrics
-
-import (
-	"context"
-	"sync"
-
-	"github.com/ipfs/go-metrics-interface"
-)
-
-var (
-	// the 1<<18+15 is to observe old file chunks that are 1<<18 + 14 in size
-	metricsBuckets = []float64{1 << 6, 1 << 10, 1 << 14, 1 << 18, 1<<18 + 15, 1 << 22}
-
-	timeMetricsBuckets = []float64{1, 10, 30, 60, 90, 120, 600}
-)
-
-// Metrics is a type which lazy initialize metrics objects.
-// It MUST not be copied.
-type Metrics struct {
-	ctx  context.Context
-	lock sync.Mutex
-
-	dupHist      metrics.Histogram
-	allHist      metrics.Histogram
-	sentHist     metrics.Histogram
-	sendTimeHist metrics.Histogram
-
-	pendingEngineGauge metrics.Gauge
-	activeEngineGauge  metrics.Gauge
-	pendingBlocksGauge metrics.Gauge
-	activeBlocksGauge  metrics.Gauge
-}
-
-func New(ctx context.Context) *Metrics {
-	return &Metrics{ctx: metrics.CtxSubScope(ctx, "bitswap")}
-}
-
-// DupHist return recv_dup_blocks_bytes.
-// Threadsafe
-func (m *Metrics) DupHist() metrics.Histogram {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.dupHist != nil {
-		return m.dupHist
-	}
-	m.dupHist = metrics.NewCtx(m.ctx, "recv_dup_blocks_bytes", "Summary of duplicate data blocks recived").Histogram(metricsBuckets)
-	return m.dupHist
-}
-
-// AllHist returns recv_all_blocks_bytes.
-// Threadsafe
-func (m *Metrics) AllHist() metrics.Histogram {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.allHist != nil {
-		return m.allHist
-	}
-	m.allHist = metrics.NewCtx(m.ctx, "recv_all_blocks_bytes", "Summary of all data blocks recived").Histogram(metricsBuckets)
-	return m.allHist
-}
-
-// SentHist returns sent_all_blocks_bytes.
-// Threadsafe
-func (m *Metrics) SentHist() metrics.Histogram {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.sentHist != nil {
-		return m.sentHist
-	}
-	m.sentHist = metrics.NewCtx(m.ctx, "sent_all_blocks_bytes", "Histogram of blocks sent by this bitswap").Histogram(metricsBuckets)
-	return m.sentHist
-}
-
-// SendTimeHist returns send_times.
-// Threadsafe
-func (m *Metrics) SendTimeHist() metrics.Histogram {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.sendTimeHist != nil {
-		return m.sendTimeHist
-	}
-	m.sendTimeHist = metrics.NewCtx(m.ctx, "send_times", "Histogram of how long it takes to send messages in this bitswap").Histogram(timeMetricsBuckets)
-	return m.sendTimeHist
-}
-
-// PendingEngineGauge returns pending_tasks.
-// Threadsafe
-func (m *Metrics) PendingEngineGauge() metrics.Gauge {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.pendingEngineGauge != nil {
-		return m.pendingEngineGauge
-	}
-	m.pendingEngineGauge = metrics.NewCtx(m.ctx, "pending_tasks", "Total number of pending tasks").Gauge()
-	return m.pendingEngineGauge
-}
-
-// ActiveEngineGauge returns active_tasks.
-// Threadsafe
-func (m *Metrics) ActiveEngineGauge() metrics.Gauge {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.activeEngineGauge != nil {
-		return m.activeEngineGauge
-	}
-	m.activeEngineGauge = metrics.NewCtx(m.ctx, "active_tasks", "Total number of active tasks").Gauge()
-	return m.activeEngineGauge
-}
-
-// PendingBlocksGauge returns pending_block_tasks.
-// Threadsafe
-func (m *Metrics) PendingBlocksGauge() metrics.Gauge {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.pendingBlocksGauge != nil {
-		return m.pendingBlocksGauge
-	}
-	m.pendingBlocksGauge = metrics.NewCtx(m.ctx, "pending_block_tasks", "Total number of pending blockstore tasks").Gauge()
-	return m.pendingBlocksGauge
-}
-
-// ActiveBlocksGauge returns active_block_tasks.
-// Threadsafe
-func (m *Metrics) ActiveBlocksGauge() metrics.Gauge {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	if m.activeBlocksGauge != nil {
-		return m.activeBlocksGauge
-	}
-	m.activeBlocksGauge = metrics.NewCtx(m.ctx, "active_block_tasks", "Total number of active blockstore tasks").Gauge()
-	return m.activeBlocksGauge
-}
diff --git a/metrics/metrics.go b/metrics/metrics.go
new file mode 100644
index 00000000..8d679a51
--- /dev/null
+++ b/metrics/metrics.go
@@ -0,0 +1,44 @@
+package metrics
+
+import (
+	"github.com/ipfs/go-metrics-interface"
+)
+
+var (
+	// the 1<<18+15 is to observe old file chunks that are 1<<18 + 14 in size
+	metricsBuckets = []float64{1 << 6, 1 << 10, 1 << 14, 1 << 18, 1<<18 + 15, 1 << 22}
+
+	timeMetricsBuckets = []float64{1, 10, 30, 60, 90, 120, 600}
+)
+
+func DupHist() metrics.Histogram {
+	return metrics.New("recv_dup_blocks_bytes", "Summary of duplicate data blocks recived").Histogram(metricsBuckets)
+}
+
+func AllHist() metrics.Histogram {
+	return metrics.New("recv_all_blocks_bytes", "Summary of all data blocks recived").Histogram(metricsBuckets)
+}
+
+func SentHist() metrics.Histogram {
+	return metrics.New("sent_all_blocks_bytes", "Histogram of blocks sent by this bitswap").Histogram(metricsBuckets)
+}
+
+func SendTimeHist() metrics.Histogram {
+	return metrics.New("send_times", "Histogram of how long it takes to send messages in this bitswap").Histogram(timeMetricsBuckets)
+}
+
+func PendingEngineGauge() metrics.Gauge {
+	return metrics.New("pending_tasks", "Total number of pending tasks").Gauge()
+}
+
+func ActiveEngineGauge() metrics.Gauge {
+	return metrics.New("active_tasks", "Total number of active tasks").Gauge()
+}
+
+func PendingBlocksGauge() metrics.Gauge {
+	return metrics.New("pending_block_tasks", "Total number of pending blockstore tasks").Gauge()
+}
+
+func ActiveBlocksGauge() metrics.Gauge {
+	return metrics.New("active_block_tasks", "Total number of active blockstore tasks").Gauge()
+}
diff --git a/server/forward.go b/server/forward.go
index 67f5b2a5..79c39d5d 100644
--- a/server/forward.go
+++ b/server/forward.go
@@ -8,6 +8,7 @@ type (
 	Receipt                = decision.Receipt
 	PeerBlockRequestFilter = decision.PeerBlockRequestFilter
 	TaskComparator         = decision.TaskComparator
+	TaskInfo               = decision.TaskInfo
 	ScoreLedger            = decision.ScoreLedger
 	ScorePeerFunc          = decision.ScorePeerFunc
 )
diff --git a/server/internal/decision/engine.go b/server/internal/decision/engine.go
index d1ccdeb0..04bcb143 100644
--- a/server/internal/decision/engine.go
+++ b/server/internal/decision/engine.go
@@ -308,7 +308,6 @@ func NewEngine(
 	bs bstore.Blockstore,
 	peerTagger PeerTagger,
 	self peer.ID,
-	metrics *bmetrics.Metrics,
 	opts ...Option,
 ) *Engine {
 	return newEngine(
@@ -316,7 +315,6 @@ func NewEngine(
 		peerTagger,
 		self,
 		maxBlockSizeReplaceHasWithBlock,
-		metrics,
 		opts...,
 	)
 }
@@ -326,10 +324,8 @@ func newEngine(
 	peerTagger PeerTagger,
 	self peer.ID,
 	maxReplaceSize int,
-	metrics *bmetrics.Metrics,
 	opts ...Option,
 ) *Engine {
-
 	e := &Engine{
 		ledgerMap:                       make(map[peer.ID]*ledger),
 		scoreLedger:                     NewDefaultScoreLedger(),
@@ -344,8 +340,8 @@ func newEngine(
 		sendDontHaves:                   true,
 		self:                            self,
 		peerLedger:                      newPeerLedger(),
-		pendingGauge:                    metrics.PendingEngineGauge(),
-		activeGauge:                     metrics.ActiveEngineGauge(),
+		pendingGauge:                    bmetrics.PendingEngineGauge(),
+		activeGauge:                     bmetrics.ActiveEngineGauge(),
 		targetMessageSize:               defaultTargetMessageSize,
 		tagQueued:                       fmt.Sprintf(tagFormat, "queued", uuid.New().String()),
 		tagUseful:                       fmt.Sprintf(tagFormat, "useful", uuid.New().String()),
@@ -355,7 +351,7 @@ func newEngine(
 		opt(e)
 	}
 
-	e.bsm = newBlockstoreManager(bs, e.bstoreWorkerCount, metrics.PendingBlocksGauge(), metrics.ActiveBlocksGauge())
+	e.bsm = newBlockstoreManager(bs, e.bstoreWorkerCount, bmetrics.PendingBlocksGauge(), bmetrics.ActiveBlocksGauge())
 
 	// default peer task queue options
 	peerTaskQueueOpts := []peertaskqueue.Option{
diff --git a/server/internal/decision/engine_test.go b/server/internal/decision/engine_test.go
index 853cc3bf..3ae8f150 100644
--- a/server/internal/decision/engine_test.go
+++ b/server/internal/decision/engine_test.go
@@ -14,7 +14,6 @@ import (
 	"github.com/ipfs/go-bitswap/internal/testutil"
 	message "github.com/ipfs/go-bitswap/message"
 	pb "github.com/ipfs/go-bitswap/message/pb"
-	"github.com/ipfs/go-bitswap/metrics"
 
 	blocks "github.com/ipfs/go-block-format"
 	"github.com/ipfs/go-cid"
@@ -197,7 +196,6 @@ func newEngineForTesting(
 		peerTagger,
 		self,
 		maxReplaceSize,
-		metrics.New(ctx),
 		opts...,
 	)
 }
diff --git a/server/server.go b/server/server.go
index 8cbe4682..b39c34f1 100644
--- a/server/server.go
+++ b/server/server.go
@@ -26,14 +26,7 @@ import (
 	"go.uber.org/zap"
 )
 
-var (
-	// HasBlockBufferSize is the buffer size of the channel for new blocks
-	// that need to be provided. They should get pulled over by the
-	// provideCollector even before they are actually provided.
-	// TODO: Does this need to be this large givent that?
-	HasBlockBufferSize    = 256
-	provideKeysBufferSize = 2048
-)
+var provideKeysBufferSize = 2048
 
 var log = logging.Logger("bitswap-server")
 var sflog = log.Desugar()
@@ -74,11 +67,13 @@ type Server struct {
 	// Extra options to pass to the decision manager
 	engineOptions []decision.Option
 
+	// the size of channel buffer to use
+	hasBlockBufferSize int
 	// whether or not to make provide announcements
 	provideEnabled bool
 }
 
-func New(ctx context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Blockstore, m *bmetrics.Metrics, options ...Option) *Server {
+func New(ctx context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Blockstore, options ...Option) *Server {
 	ctx, cancel := context.WithCancel(ctx)
 
 	px := process.WithTeardown(func() error {
@@ -90,15 +85,16 @@ func New(ctx context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Bl
 	}()
 
 	s := &Server{
-		sentHistogram:     m.SentHist(),
-		sendTimeHistogram: m.SendTimeHist(),
-		taskWorkerCount:   defaults.BitswapTaskWorkerCount,
-		network:           network,
-		process:           px,
-		provideEnabled:    true,
-		newBlocks:         make(chan cid.Cid, HasBlockBufferSize),
-		provideKeys:       make(chan cid.Cid, provideKeysBufferSize),
+		sentHistogram:      bmetrics.SentHist(),
+		sendTimeHistogram:  bmetrics.SendTimeHist(),
+		taskWorkerCount:    defaults.BitswapTaskWorkerCount,
+		network:            network,
+		process:            px,
+		provideEnabled:     true,
+		hasBlockBufferSize: defaults.HasBlockBufferSize,
+		provideKeys:        make(chan cid.Cid, provideKeysBufferSize),
 	}
+	s.newBlocks = make(chan cid.Cid, s.hasBlockBufferSize)
 
 	for _, o := range options {
 		o(s)
@@ -109,7 +105,6 @@ func New(ctx context.Context, network bsnet.BitSwapNetwork, bstore blockstore.Bl
 		bstore,
 		network.ConnectionManager(),
 		network.Self(),
-		m,
 		s.engineOptions...,
 	)
 	s.engineOptions = nil
@@ -215,6 +210,16 @@ func MaxOutstandingBytesPerPeer(count int) Option {
 	}
 }
 
+// HasBlockBufferSize configure how big the new blocks buffer should be.
+func HasBlockBufferSize(count int) Option {
+	if count < 0 {
+		panic("cannot have negative buffer size")
+	}
+	return func(bs *Server) {
+		bs.hasBlockBufferSize = count
+	}
+}
+
 // WantlistForPeer returns the currently understood list of blocks requested by a
 // given peer.
 func (bs *Server) WantlistForPeer(p peer.ID) []cid.Cid {
diff --git a/client/testinstance/testinstance.go b/testinstance/testinstance.go
similarity index 100%
rename from client/testinstance/testinstance.go
rename to testinstance/testinstance.go
diff --git a/wantlist/forward.go b/wantlist/forward.go
new file mode 100644
index 00000000..c7eba707
--- /dev/null
+++ b/wantlist/forward.go
@@ -0,0 +1,23 @@
+package wantlist
+
+import (
+	"github.com/ipfs/go-bitswap/client/wantlist"
+	"github.com/ipfs/go-cid"
+)
+
+type (
+	// DEPRECATED use wantlist.Entry instead
+	Entry = wantlist.Entry
+	// DEPRECATED use wantlist.Wantlist instead
+	Wantlist = wantlist.Wantlist
+)
+
+// DEPRECATED use wantlist.New instead
+func New() *Wantlist {
+	return wantlist.New()
+}
+
+// DEPRECATED use wantlist.NewRefEntry instead
+func NewRefEntry(c cid.Cid, p int32) Entry {
+	return wantlist.NewRefEntry(c, p)
+}