docs: public static <UK, UV> byte[] serializeMap(Iterable<Map.Entry<UK, UV>> entries, TypeSerializer<UK> keySerializer, TypeSerializer<UV> valueSerializer) throws IOException {
  		if (entries != null) {
  			// Serialize
  			DataOutputSerializer dos = new DataOutputSerializer(32);
  
  			for (Map.Entry<UK, UV> entry : entries) {
  				keySerializer.serialize(entry.getKey(), dos);
  
  				if (entry.getValue() == null) {
  					dos.writeBoolean(true);
  				} else {
  					dos.writeBoolean(false);
  					valueSerializer.serialize(entry.getValue(), dos);
  				}
  			}
  
  			return dos.getCopyOfBuffer();
  		} else {
  			return null;
  		}
  	}