Keep terminal backpressure test MTU safe

tests/client_terminal_runtime.rs

@@ -436,16 +436,28 @@ fn run_backpressure_server(
                 );
             }
             PacketKind::Ack if !bulk_sent => {
-                let bulk = vec![b'x'; 60 * 1024];
+                let bulk = [b'x'; 1024];
+                for index in 0..64u64 {
+                    send_frame(
+                        &socket,
+                        peer.unwrap_or(source),
+                        PacketKind::Frame,
+                        2 + index,
+                        11 + index,
+                        &bulk,
+                        false,
+                        false,
+                    );
+                }
                 send_frame(
                     &socket,
                     peer.unwrap_or(source),
                     PacketKind::Frame,
-                    2,
-                    11,
-                    &bulk,
-                    false,
+                    66,
+                    75,
+                    b"DOSH_BACKPRESSURE_DONE",
                     false,
+                    true,
                 );
                 bulk_sent = true;
                 observations.send(ServerObservation::BulkSent).unwrap();
@@ -459,16 +471,6 @@ fn run_backpressure_server(
                     .send(ServerObservation::Input(input.bytes))
                     .unwrap();
                 if contains(&received_input, expected_input) {
-                    send_frame(
-                        &socket,
-                        peer.unwrap_or(source),
-                        PacketKind::Frame,
-                        3,
-                        12,
-                        b"DOSH_BACKPRESSURE_DONE",
-                        false,
-                        true,
-                    );
                     break;
                 }
             }