public synchronized void flush() throws IOException {
        if (sink != null) {
            if (sink.closedByReader || closed) {
                throw new IOException("Pipe closed");
            }
            synchronized (sink) {
                sink.notifyAll();
            }
        }
    }
public synchronized void flush ( ) throws IOException { if ( sink != null ) { if ( sink . closedByReader || closed ) { throw new IOException ( "Pipe closed" ) ; } synchronized ( sink ) { sink . notifyAll ( ) ; } } }
Flushes this output stream and forces any buffered output characters
to be written out.
This will notify any readers that characters are waiting in the pipe.

@exception  IOException  if the pipe is closed, or an I/O error occurs.