Remove error check in OutputStream._write

Author: fbbdev

lib/streams.js

@@ -79,11 +79,6 @@ OutputStream.prototype._close = function (hadError) {
 };
 
 OutputStream.prototype._write = function (chunk, encoding, callback) {
-    if (!this._open) {
-        callback(new Error("Output stream is not open"));
-        return;
-    }
-
     var chunks = [];
 
     if (!Buffer.isBuffer(chunk)) {