@Override
        public int hashCode() {
            return Objects.hash(name,
                    argType,
                    optional,
                    varargs,
                    minVarargsCount,
                    description,
                    allowedValues,
                    defaultValue);
        }
@return True if this function signature is overloaded within its category
stroom-core-shared/src/main/java/stroom/query/shared/QueryHelpFunctionSignature.java