Function DirectFunctionCall3Coll 

pub unsafe fn DirectFunctionCall3Coll(
    arg_func: Option<unsafe extern "C-unwind" fn(*mut FunctionCallInfoBaseData) -> Datum>,
    arg_collation: Oid,
    arg_arg1: Datum,
    arg_arg2: Datum,
    arg_arg3: Datum,
) -> Datum