code: public static Throwable deserializeServerFailure(final ByteBuf buf) throws IOException, ClassNotFoundException {
  		try (ByteBufInputStream bis = new ByteBufInputStream(buf);
  				ObjectInputStream in = new ObjectInputStream(bis)) {
  			return (Throwable) in.readObject();
  		}
  	}
docs: De-serializes the failure message sent to the
  {@link org.apache.flink.queryablestate.network.Client} in case of
  server related errors.
  <pre>
  <b>The buffer is expected to be at the correct position.</b>
  </pre>
  @param buf	The {@link ByteBuf} containing the serialized failure message.
  @return		The failure message.