code: static <T> ProtofieldEncoder<T> makeNullableFieldEncoder(final ProtofieldEncoder<T> baseEncoder, final boolean isNullable) {
  		if ( isNullable ) {
  			return (ProtoStreamWriter outProtobuf, T value) -> {
  				if ( value != null ) {
  					baseEncoder.encode( outProtobuf, value );
  				}
  			};
  		}
  		else {
  			return baseEncoder;
  		}
  	}
docs: Wrap a ProtofieldEncoder function into another ProtofieldEncoder which adds it capabilities
  to deal with encoding of optional (nullable) values.
  @param baseEncoder the ProtofieldEncoder to use normally
  @param isNullable if true we'll wrap it, otherwise the baseEncoder is returned untouched.
  @return