[Socket] Buffer fix

Removed the option for output buffer chunk size, use defaults
Removed the unit test that check specific string on error
Unit test just checks an exception was thrown on an invalid write

Buffer.php

@@ -10,7 +10,6 @@ class Buffer extends EventEmitter
     public $socket;
     public $closed = false;
     public $listening = false;
-    public $chunkSize = 4096;
     private $loop;
     private $data = '';
 
@@ -46,7 +45,7 @@ public function end()
 
     public function handleWrite()
     {
-        $sent = @fwrite($this->socket, $this->data, $this->chunkSize);
+        $sent = @fwrite($this->socket, $this->data);
 
         if (false === $sent) {
             $this->emit('error', array(new \RuntimeException('Unable to write to socket')));