convert std::sync::mpsc to crossbeam_channel (#22264)

banks-server/Cargo.toml

@@ -11,6 +11,7 @@ edition = "2021"
 
 [dependencies]
 bincode = "1.3.3"
+crossbeam-channel = "0.5"
 futures = "0.3"
 solana-banks-interface = { path = "../banks-interface", version = "=1.10.0" }
 solana-runtime = { path = "../runtime", version = "=1.10.0" }

banks-server/src/banks_server.rs

@@ -1,5 +1,6 @@
 use {
     bincode::{deserialize, serialize},
+    crossbeam_channel::{unbounded, Receiver, Sender},
     futures::{future, prelude::stream::StreamExt},
     solana_banks_interface::{
         Banks, BanksRequest, BanksResponse, BanksTransactionResultWithSimulation,
@@ -30,10 +31,7 @@ use {
         convert::TryFrom,
         io,
         net::{Ipv4Addr, SocketAddr},
-        sync::{
-            mpsc::{channel, Receiver, Sender},
-            Arc, RwLock,
-        },
+        sync::{Arc, RwLock},
         thread::Builder,
         time::Duration,
     },
@@ -96,7 +94,7 @@ impl BanksServer {
         block_commitment_cache: Arc<RwLock<BlockCommitmentCache>>,
         poll_signature_status_sleep_duration: Duration,
     ) -> Self {
-        let (transaction_sender, transaction_receiver) = channel();
+        let (transaction_sender, transaction_receiver) = unbounded();
         let bank = bank_forks.read().unwrap().working_bank();
         let slot = bank.slot();
         {
@@ -392,7 +390,7 @@ pub async fn start_tcp_server(
         // serve is generated by the service attribute. It takes as input any type implementing
         // the generated Banks trait.
         .map(move |chan| {
-            let (sender, receiver) = channel();
+            let (sender, receiver) = unbounded();
 
             SendTransactionService::new::<NullTpuInfo>(
                 tpu_addr,