Add quic-client module (#23166)

* Add quic-client module to send transactions via quic, abstracted behind the TpuConnection trait (along with a legacy UDP implementation of TpuConnection) and change thin-client to use TpuConnection

client/src/udp_client.rs

@@ -0,0 +1,42 @@
+//! Simple TPU client that communicates with the given UDP port with UDP and provides
+//! an interface for sending transactions
+
+use {
+    crate::tpu_connection::TpuConnection,
+    solana_sdk::{transaction::Transaction, transport::Result as TransportResult},
+    std::net::{SocketAddr, UdpSocket},
+};
+
+pub struct UdpTpuConnection {
+    socket: UdpSocket,
+    addr: SocketAddr,
+}
+
+impl TpuConnection for UdpTpuConnection {
+    fn new(client_socket: UdpSocket, tpu_addr: SocketAddr) -> Self {
+        Self {
+            socket: client_socket,
+            addr: tpu_addr,
+        }
+    }
+
+    fn tpu_addr(&self) -> &SocketAddr {
+        &self.addr
+    }
+
+    fn send_wire_transaction(&self, data: Vec<u8>) -> TransportResult<()> {
+        self.socket.send_to(&data[..], self.addr)?;
+        Ok(())
+    }
+
+    fn send_batch(&self, transactions: Vec<Transaction>) -> TransportResult<()> {
+        transactions
+            .into_iter()
+            .map(|tx| bincode::serialize(&tx).expect("serialize Transaction in send_batch"))
+            .try_for_each(|buff| -> TransportResult<()> {
+                self.socket.send_to(&buff[..], self.addr)?;
+                Ok(())
+            })?;
+        Ok(())
+    }
+}