Leverage arrow function syntax for closure

Author: tigitz

Process.php

@@ -1253,9 +1253,7 @@ private function getDescriptors(): array
     protected function buildCallback(callable $callback = null): \Closure
     {
         if ($this->outputDisabled) {
-            return function ($type, $data) use ($callback): bool {
-                return null !== $callback && $callback($type, $data);
-            };
+            return fn ($type, $data): bool => null !== $callback && $callback($type, $data);
         }
 
         $out = self::OUT;

Tests/ProcessTest.php

@@ -155,7 +155,7 @@ public function testWaitUntilCanReturnFalse()
     {
         $p = $this->getProcess('echo foo');
         $p->start();
-        $this->assertFalse($p->waitUntil(function () { return false; }));
+        $this->assertFalse($p->waitUntil(fn () => false));
     }
 
     public function testAllOutputIsActuallyReadOnTermination()