errorMessage: Improvement in the error thrown in case of writable st…

lib/_stream_writable.js

@@ -197,6 +197,7 @@ function validChunk(stream, state, chunk, cb) {
 }
 
 Writable.prototype.write = function(chunk, encoding, cb) {
+
   var state = this._writableState;
   var ret = false;
 
@@ -305,6 +306,7 @@ function doWrite(stream, state, writev, len, chunk, encoding, cb) {
     stream._writev(chunk, state.onwrite);
   else
     stream._write(chunk, encoding, state.onwrite);
+
   state.sync = false;
 }
 
@@ -432,7 +434,7 @@ function clearBuffer(stream, state) {
 }
 
 Writable.prototype._write = function(chunk, encoding, cb) {
-  cb(new Error('not implemented'));
+  cb(new Error('Write method cannot be invoked on the Writable stream . Method not implemented'));
 };
 
 Writable.prototype._writev = null;