code: private static <UK> UK deserializeUserKey(
  		DataInputDeserializer dataInputView,
  		int userKeyOffset,
  		byte[] rawKeyBytes,
  		TypeSerializer<UK> keySerializer) throws IOException {
  		dataInputView.setBuffer(rawKeyBytes, userKeyOffset, rawKeyBytes.length - userKeyOffset);
  		return keySerializer.deserialize(dataInputView);
  	}
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