Function transmit_qos0 

pub fn transmit_qos0<B, A>(
    out: &mut PacketWriter<B>,
    aliases: &mut A,
    max_packet_size: Option<u32>,
    topic: &Topic,
    retain: bool,
    properties: &PublishProperties,
    payload: &[u8],
) -> bool
where
    B: ByteBuffer,
    A: TopicAliasTable,

Encodes a QoS 0 (fire-and-forget) PUBLISH into out.

Resolves the topic alias and enforces the Maximum Packet Size, like the session drain, but QoS 0 carries no session state so this is a free function. Returns true if the packet was written, false if it was dropped (too large, or the buffer is full).