Function async_coap::message::codec::insert_option

pub fn insert_option(
    buffer: &mut [u8], 
    len: usize, 
    last_option: OptionNumber, 
    key: OptionNumber, 
    value: &[u8]
) -> Result<(usize, OptionNumber), Error>

Inserts an option into an option list. Very slow unless called sequentially.