arm: async uart writes & fixes

arm/buffer.h

@@ -2,22 +2,29 @@
 
 #include <span>
 #include <utility>
- 
+
 struct buffer {
-  std::span<std::byte> data;
- 
-  buffer() = default;
-  buffer(std::span<std::byte> d) : data(d) {}
- 
-  static buffer make(size_t size) {
-    return buffer({new std::byte[size], size});
-  }
- 
-  buffer(buffer& other) = delete;
-  buffer& operator=(buffer& other) = delete;
- 
-  buffer(buffer&& other) : data(std::exchange(other.data, {})) {}
-  buffer& operator=(buffer&& other) { data = std::exchange(other.data, {}); return *this; }
- 
-  ~buffer() { if (data.data()) { delete[] data.data(); }; }
+    std::span<std::byte> data;
+
+    buffer() = default;
+    buffer(std::span<std::byte> d) : data(d) {}
+
+    static buffer make(size_t size) {
+        return buffer({new std::byte[size], size});
+    }
+
+    buffer(buffer& other) = delete;
+    buffer& operator=(buffer& other) = delete;
+
+    buffer(buffer&& other) : data(std::exchange(other.data, {})) {}
+    buffer& operator=(buffer&& other) {
+        data = std::exchange(other.data, {});
+        return *this;
+    }
+
+    ~buffer() {
+        if (data.data()) {
+            delete[] data.data();
+        };
+    }
 };