Function drain_queued_commands 

async fn drain_queued_commands<W: AsyncWrite + Unpin>(
    queued: &mut VecDeque<Command>,
    client: &mut Client<JournaledSession>,
    writer: &mut W,
    pending: &mut Pending,
    max_packet_size: Option<u32>,
    outbound_aliases: &mut OutboundAliases,
) -> Option<DisconnectReason>