Fix rust-fmt + add comment.

Author: MA-ETL

src/io/sendmsg_zc.rs

@@ -1,4 +1,3 @@
-//use crate::buf::BoundedBuf;
 use crate::io::SharedFd;
 use crate::runtime::driver::op::{Completable, CqeResult, MultiCQEFuture, Op, Updateable};
 use crate::runtime::CONTEXT;
@@ -22,27 +21,31 @@ impl Op<SendMsgZc, MultiCQEFuture> {
             x.handle().expect("Not in a runtime context").submit_op(
                 SendMsgZc {
                     fd: fd.clone(),
-                    msghdr: msghdr.clone(),
+                    msghdr: msghdr.copy(),
                     bytes: 0,
                 },
                 |sendmsg_zc| {
-                    opcode::SendMsgZc::new(types::Fd(sendmsg_zc.fd.raw_fd()), &sendmsg_zc.msghdr as *const _).build()
+                    opcode::SendMsgZc::new(
+                        types::Fd(sendmsg_zc.fd.raw_fd()), 
+                        &sendmsg_zc.msghdr as *const _
+                    )
+                    .build()
                 },
             )
         })
     }
 }
 
 impl Completable for SendMsgZc {
-    type Output = (libc::msghdr, io::Result<usize>) ;
+    type Output = (libc::msghdr, io::Result<usize>);
 
     fn complete(self, cqe: CqeResult) -> (libc::msghdr, io::Result<usize>) {
         // Convert the operation result to `usize`
         let res = cqe.result.map(|v| v as usize);
 
         // Recover the msghdr.
         let msghdr = self.msghdr;
-    
+
         (msghdr, res)
     }
 }

src/io/socket.rs

@@ -147,7 +147,10 @@ impl Socket {
         op.await
     }
 
-    pub(crate) async fn sendmsg_zc(&self, msghdr: &libc::msghdr) -> (libc::msghdr, io::Result<usize>) {
+    pub(crate) async fn sendmsg_zc(
+        &self, 
+        msghdr: &libc::msghdr
+    ) -> (libc::msghdr, io::Result<usize>) {
         let op = Op::sendmsg_zc(&self.fd, msghdr).unwrap();
         op.await
     }

src/net/udp.rs

@@ -220,7 +220,8 @@ impl UdpSocket {
         self.inner.send_zc(buf).await
     }
 
-    pub async fn sendmsg_zc(&self, msghdr: &libc::msghdr) -> (libc::msghdr, io::Result<usize>)  {
+    /// Sends a message on the socket using a msghdr.
+    pub async fn sendmsg_zc(&self, msghdr: &libc::msghdr) -> (libc::msghdr, io::Result<usize>) {
         self.inner.sendmsg_zc(msghdr).await
     }