Function mqttrs::encode_slice

pub fn encode_slice(packet: &Packet<'_>, buf: &mut [u8]) -> Result<usize, Error>

Encode a Packet enum into a BufMut buffer.

// Instantiate a `Packet` to encode.
let packet = Publish {
   dup: false,
   qospid: QosPid::AtMostOnce,
   retain: false,
   topic_name: "test",
   payload: b"hello",
}.into();

// Allocate buffer (should be appropriately-sized or able to grow as needed).
let mut buf = [0u8; 1024];

// Write bytes corresponding to `&Packet` into the `BytesMut`.
let len = encode_slice(&packet, &mut buf).expect("failed encoding");
assert_eq!(&buf[..len], &[0b00110000, 11,
                    0, 4, 't' as u8, 'e' as u8, 's' as u8, 't' as u8,
                   'h' as u8, 'e' as u8, 'l' as u8, 'l' as u8, 'o' as u8]);