code: @Override
      public void setReceiveBufferSize(int receiveBufferSize) {
          try {
              if (ENABLE_BUFFER_SIZE) {
                  System.out.println("NioDatagramSessionConfig.setReceiveBufferSize(" + receiveBufferSize + ")");
                  channel.socket().setReceiveBufferSize(receiveBufferSize);
              }
          } catch (SocketException e) {
              throw new RuntimeIoException(e);
          }
      }
docs: Set the Socket receive buffer size for this DatagramChannel. <br>
  <br>
  Note : The underlying Socket may not accept the new buffer's size.
  The user has to check that the new value has been set.
  
  @param receiveBufferSize the DatagramChannel receive buffer size.
  @throws RuntimeIoException if the socket is closed or if we
  had a SocketException
  
  @see DatagramSocket#setReceiveBufferSize()