refactor(proxy): improve tunnel throughput and observability

apps/aether-proxy/src/tunnel/mod.rs

@@ -509,6 +509,7 @@ mod tests {
             aether_retry_max_attempts: 1,
             aether_retry_base_delay_ms: 50,
             aether_retry_max_delay_ms: 100,
+            diagnostics_bind: None,
             max_concurrent_connections: None,
             max_in_flight_streams: None,
             distributed_stream_limit: None,
@@ -526,6 +527,7 @@ mod tests {
             upstream_tcp_nodelay: true,
             upstream_proxy_url: None,
             redirect_replay_budget_bytes: crate::config::DEFAULT_REDIRECT_REPLAY_BUDGET_BYTES,
+            emit_proxy_timing_header: true,
             log_level: "info".to_string(),
             log_destination: crate::config::ProxyLogDestinationArg::Stdout,
             log_dir: None,