diff --git a/src/FulfilledPromise.php b/src/FulfilledPromise.php
index fd6d6337..caa98336 100644
--- a/src/FulfilledPromise.php
+++ b/src/FulfilledPromise.php
@@ -22,7 +22,7 @@ public function then(callable $onFulfilled = null, callable $onRejected = null)
         }
 
         return new Promise(function (callable $resolve, callable $reject) use ($onFulfilled) {
-            Queue::enqueue(function () use ($resolve, $reject, $onFulfilled) {
+            enqueue(function () use ($resolve, $reject, $onFulfilled) {
                 try {
                     $resolve($onFulfilled($this->value));
                 } catch (\Throwable $exception) {
@@ -40,7 +40,7 @@ public function done(callable $onFulfilled = null, callable $onRejected = null)
             return;
         }
 
-        Queue::enqueue(function () use ($onFulfilled) {
+        enqueue(function () use ($onFulfilled) {
             $result = $onFulfilled($this->value);
 
             if ($result instanceof PromiseInterface) {
diff --git a/src/Queue/SynchronousDriver.php b/src/Internal/Queue.php
similarity index 88%
rename from src/Queue/SynchronousDriver.php
rename to src/Internal/Queue.php
index 33c0372d..be1a08ea 100644
--- a/src/Queue/SynchronousDriver.php
+++ b/src/Internal/Queue.php
@@ -1,8 +1,11 @@
 <?php
 
-namespace React\Promise\Queue;
+namespace React\Promise\Internal;
 
-final class SynchronousDriver implements DriverInterface
+/**
+ * @internal
+ */
+final class Queue
 {
     private $queue = [];
 
diff --git a/src/Queue.php b/src/Queue.php
deleted file mode 100644
index afc4295e..00000000
--- a/src/Queue.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php
-
-namespace React\Promise;
-
-use React\Promise\Queue\DriverInterface;
-
-final class Queue
-{
-    /**
-     * @var DriverInterface
-     */
-    private static $driver;
-
-    public static function setDriver(DriverInterface $driver = null)
-    {
-        self::$driver = $driver;
-    }
-
-    public static function getDriver()
-    {
-        if (!self::$driver) {
-            self::$driver = new Queue\SynchronousDriver();
-        }
-
-        return self::$driver;
-    }
-
-    public static function enqueue(callable $task)
-    {
-        if (!self::$driver) {
-            self::getDriver();
-        }
-
-        self::$driver->enqueue($task);
-    }
-}
diff --git a/src/Queue/DriverInterface.php b/src/Queue/DriverInterface.php
deleted file mode 100644
index 7d2865f3..00000000
--- a/src/Queue/DriverInterface.php
+++ /dev/null
@@ -1,8 +0,0 @@
-<?php
-
-namespace React\Promise\Queue;
-
-interface DriverInterface
-{
-    public function enqueue(callable $task);
-}
diff --git a/src/RejectedPromise.php b/src/RejectedPromise.php
index 2d7549e9..adea8e2e 100644
--- a/src/RejectedPromise.php
+++ b/src/RejectedPromise.php
@@ -22,7 +22,7 @@ public function then(callable $onFulfilled = null, callable $onRejected = null)
         }
 
         return new Promise(function (callable $resolve, callable $reject) use ($onRejected) {
-            Queue::enqueue(function () use ($resolve, $reject, $onRejected) {
+            enqueue(function () use ($resolve, $reject, $onRejected) {
                 try {
                     $resolve($onRejected($this->reason));
                 } catch (\Throwable $exception) {
@@ -36,7 +36,7 @@ public function then(callable $onFulfilled = null, callable $onRejected = null)
 
     public function done(callable $onFulfilled = null, callable $onRejected = null)
     {
-        Queue::enqueue(function () use ($onRejected) {
+        enqueue(function () use ($onRejected) {
             if (null === $onRejected) {
                 throw UnhandledRejectionException::resolve($this->reason);
             }
diff --git a/src/functions.php b/src/functions.php
index 479b2c9a..6b32daf2 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -189,6 +189,20 @@ function reduce(array $promisesOrValues, callable $reduceFunc, $initialValue = n
     }, $cancellationQueue);
 }
 
+/**
+ * @internal
+ */
+function enqueue(callable $task)
+{
+    static $queue;
+
+    if (!$queue) {
+        $queue = new Internal\Queue();
+    }
+
+    $queue->enqueue($task);
+}
+
 /**
  * @internal
  */
diff --git a/tests/Internal/QueueTest.php b/tests/Internal/QueueTest.php
new file mode 100644
index 00000000..14fde6bb
--- /dev/null
+++ b/tests/Internal/QueueTest.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace React\Promise\Internal;
+
+use React\Promise\TestCase;
+
+class QueueTest extends TestCase
+{
+    /** @test */
+    public function excutesTasks()
+    {
+        $queue = new Queue();
+
+        $queue->enqueue($this->expectCallableOnce());
+        $queue->enqueue($this->expectCallableOnce());
+    }
+
+    /** @test */
+    public function excutesNestedEnqueuedTasks()
+    {
+        $queue = new Queue();
+
+        $nested = $this->expectCallableOnce();
+
+        $task = function() use ($queue, $nested) {
+            $queue->enqueue($nested);
+        };
+
+        $queue->enqueue($task);
+    }
+
+    /** @test */
+    public function rethrowsExceptionsThrownFromTasks()
+    {
+        $this->setExpectedException('\Exception', 'test');
+
+        $mock = $this->createCallableMock();
+        $mock
+            ->expects($this->once())
+            ->method('__invoke')
+            ->will($this->throwException(new \Exception('test')));
+
+        $queue = new Queue();
+        $queue->enqueue($mock);
+    }
+}
diff --git a/tests/QueueTest.php b/tests/QueueTest.php
deleted file mode 100644
index 4846649d..00000000
--- a/tests/QueueTest.php
+++ /dev/null
@@ -1,22 +0,0 @@
-<?php
-
-namespace React\Promise;
-
-class QueueTest extends TestCase
-{
-    /** @test */
-    public function canSetDriver()
-    {
-        $oldDriver = Queue::getDriver();
-
-        $newDriver = $this
-            ->getMockBuilder('React\Promise\Queue\DriverInterface')
-            ->getMock();
-
-        Queue::setDriver($newDriver);
-
-        $this->assertSame($newDriver, Queue::getDriver());
-
-        Queue::setDriver($oldDriver);
-    }
-}