clearLine method
Clears the current line of this stream in a direction identified by dir.
Returns false if the stream wishes for the calling code to wait for the
'drain' event to be emitted before continuing to write additional data;
otherwise returns true.
The dir argument can be set to:
-1: to the left from cursor
1: to the right from cursor
0: the entire line
Implementation
external bool clearLine(num dir, [void Function() callback]);