feat(s2n-quic-dc): Reuse handshakes across application processes (#2854)

Author: mehnazyunus

dc/s2n-quic-dc/Cargo.toml

@@ -61,7 +61,7 @@ zerocopy = { version = "0.8", features = ["derive"] }
 zeroize = "1"
 parking_lot = "0.12"
 bitvec = { version = "1.0.1", default-features = false }
-nix = {version = "0.30.1", features = ["socket", "uio", "fs"] }
+nix = {version = "0.30.1", features = ["socket", "uio", "fs", "time"] }
 
 [dev-dependencies]
 bach = { version = "0.1.0", features = ["net", "tokio-compat"] }

dc/s2n-quic-dc/events/acceptor.rs

@@ -192,6 +192,55 @@ struct AcceptorTcpIoError<'a> {
     error: &'a std::io::Error,
 }
 
+/// Emitted when the TCP stream has been sent over a Unix domain socket
+#[event("acceptor:tcp:socket_sent")]
+#[subject(endpoint)]
+struct AcceptorTcpSocketSent<'a>   {
+    /// The credential ID of the stream
+    #[snapshot("[HIDDEN]")]
+    credential_id: &'a [u8],
+
+    /// The ID of the stream
+    stream_id: u64,
+
+    /// The amount of time the TCP stream spent in the queue before being sent over Unix domain socket
+    #[timer("sojourn_time")]
+    sojourn_time: core::time::Duration,
+
+    /// The number of times the Unix domain socket was blocked on send
+    #[counter("blocked_count_host")]
+    #[measure("blocked_count_stream")]
+    blocked_count: usize,
+
+    /// The len of the payload sent over the Unix domain socket
+    #[measure("len", Bytes)]
+    payload_len: usize,
+}
+
+/// Emitted when a TCP stream has been received from a Unix domain socket
+#[event("acceptor:tcp:socket_received")]
+#[subject(endpoint)]
+struct AcceptorTcpSocketReceived<'a>   {
+    /// The address of the stream's peer
+    #[builder(&'a s2n_quic_core::inet::SocketAddress)]
+    remote_address: SocketAddress<'a>,
+    
+    /// The credential ID of the stream
+    #[snapshot("[HIDDEN]")]
+    credential_id: &'a [u8],
+
+    /// The ID of the stream
+    stream_id: u64,
+
+    /// The amount of time taken from socket send to socket receive, including waiting if the kernel queue is full
+    #[timer("transfer_time")]
+    transfer_time: core::time::Duration,
+
+    /// The len of the payload sent over the Unix domain socket
+    #[measure("len", Bytes)]
+    payload_len: usize,
+}
+
 /// Emitted when a UDP acceptor is started
 #[event("acceptor:udp:started")]
 #[subject(endpoint)]