Another round of optimization

src/engine/audio.rs

@@ -281,6 +281,8 @@ pub fn build_stream(
 
     let (mut fft_producer, analysis_handle) = spawn_analysis_thread(sample_rate, spectrum_buffer);
 
+    let mut cmd_buffer = String::with_capacity(256);
+
     let stream = device
         .build_output_stream(
             &stream_config,
@@ -291,11 +293,16 @@ pub fn build_stream(
                 while let Ok(cmd) = audio_rx.try_recv() {
                     match cmd {
                         AudioCommand::Evaluate { cmd, time } => {
-                            let cmd_with_time = match time {
-                                Some(t) => format!("{cmd}/time/{t:.6}"),
-                                None => cmd,
+                            let cmd_ref = match time {
+                                Some(t) => {
+                                    cmd_buffer.clear();
+                                    use std::fmt::Write;
+                                    let _ = write!(&mut cmd_buffer, "{cmd}/time/{t:.6}");
+                                    cmd_buffer.as_str()
+                                }
+                                None => &cmd,
                             };
-                            engine.evaluate(&cmd_with_time);
+                            engine.evaluate(cmd_ref);
                         }
                         AudioCommand::Hush => {
                             engine.hush();