code: public static void waitWhileState(final DeviceProxy proxy, final DevState waitState, final long timeout)
  	    throws DevFailed, TimeoutException {
  	waitWhileState(proxy, waitState, timeout, 300);
      }
docs: Wait while waitState does not change
  
  @param proxy
  the proxy on which to monitor the state
  @param waitState
  the state to wait
  @param timeout
  a timeout in ms
  @throws DevFailed
  @throws TimeoutException