feat: remove tasker dependency

in favour of native timeouts

shard.yml

@@ -1,12 +1,7 @@
 name: promise
-version: 2.2.2
+version: 2.2.3
 crystal: ">= 0.36.1"
 
-dependencies:
-  tasker:
-    github: spider-gazelle/tasker
-    version: ~> 2.0
-
 development_dependencies:
   ameba:
     github: veelenga/ameba

spec/promise_spec.cr

@@ -488,7 +488,10 @@ describe Promise do
       p1 = Promise.new(Symbol)
       p2 = Promise.new(String)
       spawn(same_thread: true) { p2.resolve("testing") }
-      delay(0.002) { p1.resolve(:foo) }
+      spawn do
+        sleep 0.002
+        p1.resolve(:foo)
+      end
       val = Promise.race(p1, p2).get
       val.should eq "testing"
     end
@@ -508,7 +511,10 @@ describe Promise do
       p1 = Promise.new(Symbol)
       p2 = Promise.new(String)
       spawn(same_thread: true) { p2.reject("testing") }
-      delay(0.002) { p1.resolve(:foo) }
+      spawn do
+        sleep 0.002
+        p1.resolve(:foo)
+      end
 
       begin
         val = Promise.race(p1, p2).get

src/promise.cr

@@ -1,5 +1,3 @@
-require "tasker"
-
 abstract class Promise
   class Generic(Output)
     macro get_type_var
@@ -20,12 +18,22 @@ abstract class Promise
   class Timeout < Exception
   end
 
+  def self.timeout(promise : Promise, time : Time::Span)
+    cancel = Channel(Bool).new(1)
+    promise.then { cancel.send(true) }
+
+    select
+    when cancel.receive
+    when timeout(time)
+      promise.reject(::Promise::Timeout.new("operation timeout"))
+    end
+  end
+
   macro new(type, timeout = nil)
     {% if timeout %}
       begin
         %promise = ::Promise::DeferredPromise({{type.id}}).new
-        %task = Tasker.in({{timeout}}) { %promise.reject(::Promise::Timeout.new("operation timeout")) }
-        %promise.finally { %task.cancel }
+        spawn { ::Promise.timeout(%promise, {{timeout}}) }
         %promise
       end
     {% else %}
@@ -42,8 +50,7 @@ abstract class Promise
       }.execute!
 
       {% if timeout %}
-        %task = Tasker.in({{timeout}}) { %promise.reject(::Promise::Timeout.new("operation timeout")) }
-        %promise.finally { |err| %task.cancel unless err.is_a?(::Promise::Timeout) }
+        spawn { ::Promise.timeout(%promise, {{timeout}}) }
         %promise
       {% end %}