add comment for size of channel

send-transaction-service/src/transaction_client.rs

@@ -230,6 +230,11 @@ where
     where
         T: TpuInfoWithSendStatic + Clone,
     {
+        // The channel size is a compromise value designed to prevent packet
+        // loss during outages lasting up to (128 * batch_size / rpc_tps)
+        // seconds.
+        // For a reasonable batch_size of 64 and rpc_tps of approximately 1000 transactions per second,
+        // this channel size can handle an outage of up to 8 seconds without dropping packets.
         let (sender, receiver) = mpsc::channel(128);
 
         let cancel = CancellationToken::new();