Release locks synchronously

Only release locks asynchronously on implicit unlock by the destructor.

Fixes #22.

src/Lock.php

@@ -2,7 +2,7 @@
 
 namespace Amp\Sync;
 
-use Revolt\EventLoop;
+use function Amp\async;
 
 /**
  * A handle on an acquired lock from a synchronization object.
@@ -45,8 +45,10 @@ public function release(): void
  }
 
  // Invoke the releaser function given to us by the synchronization source to release the lock.
- EventLoop::queue($this->release);
+ $release = $this->release;
  $this->release = null;
+
+ $release();
  }
 
  /**
@@ -55,7 +57,7 @@ public function release(): void
  public function __destruct()
  {
  if (!$this->isReleased()) {
- $this->release();
+ async($this->release(...));
  }
  }
 }