You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: clients.rs
    path of file: ./repos/iroh/iroh-net/src/derp
    
    the code of the file until where you have to start completion: //! based on tailscale/derp/derp_server.go
//!
//! The "Server" side of the client. Uses the `ClientConnManager`.
use crate::key::PublicKey;
use std::collections::{HashMap, HashSet};

use futures::future::join_all;
use tokio::sync::mpsc;

use iroh_metrics::inc;
use tracing::{Instrument, Span};

use super::{
    client_conn::{ClientConnBuilder, Clie
    
    pub fn send_packet(&self, packet: Packet) -> Result<(), SendError> {
        let res = try_send(&self.conn.client_channels.send_queue, packet);
        if res.is_ok() {
            // there is a chance that we have a packet forwarder for
            // this peer, so we must check that route before
            // marking the packet as "dropped"
            inc!(Metrics, send_packets_sent);
        }
        res
    }