adds initial rcs implementation

ground/src/telemetry.rs

@@ -1,7 +1,7 @@
 use api::client::Client;
 use api::client::telemetry::{TelemetryHandle, TelemetryRegistry};
-use futures::TryFutureExt;
-use futures::future::join_all;
+use futures::future::{Either, join_all, select};
+use futures::{TryFutureExt, pin_mut};
 use log::{error, trace};
 use nautilus_common::on_drop::on_drop;
 use nautilus_common::telemetry::{CommsState, SwitchBank, Telemetry, TelemetryMessage};
@@ -12,7 +12,7 @@ use std::sync::Arc;
 use tokio::net::UdpSocket;
 use tokio::sync::{RwLock, RwLockWriteGuard};
 use tokio::task::yield_now;
-use tokio::{join, pin, select, try_join};
+use tokio::{join, select, try_join};
 use tokio_util::sync::CancellationToken;
 
 pub struct TelemetryHandler<'a> {
@@ -52,7 +52,18 @@ impl<'a> TelemetryHandler<'a> {
             .build()?;
 
         runtime.block_on(async {
-            let mut context = TelemetryContext::new(&self).await;
+            // Allow cancellation while waiting for this to initialize
+            let mut context = {
+                let context = TelemetryContext::new(&self);
+                pin_mut!(context);
+                let cancellation_future = self.cancel.cancelled();
+                pin_mut!(cancellation_future);
+                let init_or_cancel = select(context, cancellation_future).await;
+                match init_or_cancel {
+                    Either::Left((success, _)) => success,
+                    Either::Right(_) => return Ok(()),
+                }
+            };
 
             let mut buffer = [0u8; 512];
 
@@ -75,7 +86,7 @@ impl<'a> TelemetryHandler<'a> {
                                     // Update the value in the lock
                                     *lock = addr;
                                 };
-                                pin!(flight_addr_update);
+                                tokio::pin!(flight_addr_update);
 
                                 // We can do these two operations concurrently
                                 join!(