Do not emit WriteStream's drain event before ws.write has been called.

lib/fs.js

@@ -840,7 +840,10 @@ WriteStream.prototype.flush = function () {
   var self = this;
 
   var args = this._queue.shift();
-  if (!args) return self.emit('drain');
+  if (!args) {
+    if (this.drainable) { self.emit('drain'); }
+    return;
+  }
 
   this.busy = true;
 
@@ -896,6 +899,8 @@ WriteStream.prototype.write = function (data) {
     throw new Error('stream not writeable');
   }
 
+  this.drainable = true;
+
   var cb;
   if (typeof(arguments[arguments.length-1]) == 'function') {
     cb = arguments[arguments.length-1];

test/simple/test-fs-write-stream.js

@@ -17,3 +17,12 @@ var file = path.join(common.fixturesDir, "write.txt");
   stream.destroy();
 })();
 
+(function() {
+  var stream = fs.createWriteStream(file);
+  
+  stream.addListener('drain', function () {
+    assert.fail('"drain" event must not be emitted before stream.write() has been called at least once.')
+  });
+  stream.destroy();
+})();
+