Macro decoder_functions 

macro_rules! decoder_functions {
    (
        preamble = $preamble:block,
        loop_preamble = $loop_preamble:block,
        eof = $eof:block,
        body = $body:block,
        self = $slf:ident,
        src_consumed = $src_consumed:ident,
        dest = $dest:ident,
        source = $source:ident,
        byte = $b:ident,
        destination_handle = $destination_handle:ident,
        unread_handle = $unread_handle:ident,
        destination_check = $destination_check:ident
    ) => { ... };
}