24 use crate::error::Result;
28     async fn connect(&self, addr: SocketAddr) -> Result<()>;  in connect()  argument
29     async fn recv(&self, buf: &mut [u8]) -> Result<usize>;  in recv()
30     async fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>;  in recv_from()
31     async fn send(&self, buf: &[u8]) -> Result<usize>;  in send()
32     async fn send_to(&self, buf: &[u8], target: SocketAddr) -> Result<usize>;  in send_to()
33     fn local_addr(&self) -> Result<SocketAddr>;  in local_addr()
35     async fn close(&self) -> Result<()>;  in close()  argument
43     async fn accept(&self) -> Result<(Arc<dyn Conn + Send + Sync>, SocketAddr)>;  in accept()
47     async fn close(&self) -> Result<()>;  in close()  argument
50     async fn addr(&self) -> Result<SocketAddr>;  in addr()
53 pub async fn lookup_host<T>(use_ipv4: bool, host: T) -> Result<SocketAddr>  in lookup_host()