Function coap_build_empty_ack

pub unsafe extern "C" fn coap_build_empty_ack(
    pkt: *mut coap_pkt_t,
    ack: *mut coap_hdr_t,
) -> ssize_t

@brief Build empty reply to CoAP request

This function can be used to create an empty ACK so that a later, separate response can be sent independently.

If the request was non-confirmable, this will generate nothing.

@param[in] pkt packet to reply to @param[out] ack buffer to write reply to

@returns size of reply packet on success @returns -ENOSPC if @p rbuf too small