refactor: Avoid using to_string when writing cursors

src/cmd.rs

@@ -144,19 +144,22 @@ where
     cmd.extend_from_slice(b"\r\n");
 
     {
-        let mut encode = |item: &[u8]| {
+        let mut cursor_bytes = [0; 20];
+        for item in args {
+            let bytes = match item {
+                Arg::Cursor => {
+                    let n = ::itoa::write(&mut cursor_bytes[..], cursor).unwrap();
+                    &cursor_bytes[..n]
+                }
+                Arg::Simple(val) => val,
+            };
+
             cmd.push(b'$');
-            ::itoa::write(&mut *cmd, item.len()).unwrap();
-            cmd.extend_from_slice(b"\r\n");
-            cmd.extend_from_slice(item);
+            ::itoa::write(&mut *cmd, bytes.len()).unwrap();
             cmd.extend_from_slice(b"\r\n");
-        };
 
-        for item in args {
-            match item {
-                Arg::Cursor => encode(cursor.to_string().as_bytes()),
-                Arg::Simple(val) => encode(val),
-            }
+            cmd.extend_from_slice(bytes);
+            cmd.extend_from_slice(b"\r\n");
         }
     }
 }