@Override
  public void flush() throws IOException {
    Set<OutputStream> outputStreams = streams;
    for (OutputStream out : outputStreams) {
      out.flush();
    }
  }
Flushes this output stream and forces any buffered output bytes to be written out to the
stream.
<p>
The <code>flush</code> method of <code>FilterOutputStream</code> calls the <code>flush</code>
method of its underlying output stream.

@exception IOException if an I/O error occurs.
@see OutputStream#flush()
geode-core/src/main/java/org/apache/geode/internal/io/CompositeOutputStream.java