diff --git a/src/Encoding/FilteredStream.php b/src/Encoding/FilteredStream.php
index 38d6258..c3a06fc 100644
--- a/src/Encoding/FilteredStream.php
+++ b/src/Encoding/FilteredStream.php
@@ -100,7 +100,7 @@ public function eof()
     protected function fill()
     {
         $readFilterCallback = $this->readFilterCallback;
-        $this->buffer      .= $readFilterCallback($this->stream->read(self::BUFFER_SIZE));
+        $this->buffer .= $readFilterCallback($this->stream->read(self::BUFFER_SIZE));
 
         if ($this->stream->eof()) {
             $this->buffer .= $readFilterCallback();