fix: Run our own async executor on Unix (#337)

platforms/unix/Cargo.toml

@@ -12,13 +12,12 @@ edition = "2021"
 
 [features]
 default = ["async-io"]
-async-io = ["dep:async-channel", "dep:async-lock", "dep:futures-util", "atspi/async-std", "zbus/async-io"]
+async-io = ["dep:async-channel", "dep:async-executor", "dep:async-task", "dep:futures-util", "atspi/async-std", "zbus/async-io"]
 tokio = ["dep:tokio", "dep:tokio-stream", "atspi/tokio", "zbus/tokio"]
 
 [dependencies]
 accesskit = { version = "0.12.2", path = "../../common" }
 accesskit_consumer = { version = "0.17.0", path = "../../consumer" }
-async-once-cell = "0.5.3"
 atspi = { version = "0.19", default-features = false }
 futures-lite = "1.13"
 once_cell = "1.17.1"
@@ -27,7 +26,8 @@ zbus = { version = "3.14", default-features = false }
 
 # async-io support
 async-channel = { version = "2.1.1", optional = true }
-async-lock = { version = "2.7.0", optional = true }
+async-executor = { version = "1.5.0", optional = true }
+async-task = { version = "4.3.0", optional = true }
 futures-util = { version = "0.3.27", optional = true }
 
 # tokio support

platforms/unix/README.md

@@ -1,3 +1,10 @@
 # AccessKit Unix adapter
 
 This is the Unix adapter for [AccessKit](https://accesskit.dev/). It exposes an AccessKit accessibility tree through the AT-SPI protocol.
+
+## Compatibility with async runtimes
+
+While this crate's API is purely blocking, it internally spawns asynchronous tasks on an executor.
+
+- If you use tokio, make sure to enable the `tokio` feature of this crate.
+- If you use another async runtime or if you don't use one at all, the default feature will suit your needs.