Function drop_and 

pub fn drop_and<Stream, Context, ParserA, ParserB>(
    parser_a: ParserA,
    parser_b: ParserB,
) -> DropAnd<ParserA, ParserB>
where
    ParserA: Parse<Stream, Context>,
    ParserB: Parse<Stream, Context>,

Function style version of crate::Utils::drop_and