Function coap_iterate_option

pub unsafe extern "C" fn coap_iterate_option(
    pkt: *mut coap_pkt_t,
    opt_num: c_uint,
    opt_pos: *mut *mut u8,
    opt_len: *mut c_int,
) -> *mut u8

@brief Get pointer to an option field, can be called in a loop if there are multiple options with the same number

@param[in] pkt packet to work on @param[in] opt_num the option number to search for @param[out] opt_pos opaque, must be set to NULL on first call @param[out] opt_len size of the current option data

@returns pointer to the option data NULL if option number was not found