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

cli/Cargo.toml

@@ -17,6 +17,7 @@ criterion-stats = "0.3.0"
 ctrlc = { version = "3.2.1", features = ["termination"] }
 console = "0.15.0"
 const_format = "0.2.22"
+crossbeam-channel = "0.5"
 log = "0.4.14"
 humantime = "2.0.1"
 num-traits = "0.2"

cli/src/cluster_query.rs

@@ -5,6 +5,7 @@ use {
     },
     clap::{value_t, value_t_or_exit, App, AppSettings, Arg, ArgMatches, SubCommand},
     console::{style, Emoji},
+    crossbeam_channel::unbounded,
     serde::{Deserialize, Serialize},
     solana_clap_utils::{
         input_parsers::*,
@@ -1368,7 +1369,7 @@ pub fn process_ping(
     println_name_value("Source Account:", &config.signers[0].pubkey().to_string());
     println!();
 
-    let (signal_sender, signal_receiver) = std::sync::mpsc::channel();
+    let (signal_sender, signal_receiver) = unbounded();
     ctrlc::set_handler(move || {
         let _ = signal_sender.send(());
     })