docs: public static <K, N> byte[] serializeKeyAndNamespace(
  			K key,
  			TypeSerializer<K> keySerializer,
  			N namespace,
  			TypeSerializer<N> namespaceSerializer) throws IOException {
  
  		DataOutputSerializer dos = new DataOutputSerializer(32);
  
  		keySerializer.serialize(key, dos);
  		dos.writeByte(MAGIC_NUMBER);
  		namespaceSerializer.serialize(namespace, dos);
  
  		return dos.getCopyOfBuffer();
  	}