presto-main/src/main/java/io/prestosql/operator/scalar/annotations/ScalarImplementationHeader.java/ScalarImplementationHeader/ScalarImplementationHeader
class ScalarImplementationHeader:    private ScalarImplementationHeader(OperatorType operatorType, ScalarHeader header)
    {
        this.name = mangleOperatorName(operatorType);
        this.operatorType = Optional.of(operatorType);
        this.header = requireNonNull(header);
    }