message: use make_shared
diff: @@ -101,7 +101,7 @@ class Builder {
  // create an empty Builder, using default Options
  Builder()
  - : _buffer(new Buffer<uint8_t>()),
  + : _buffer(std::make_shared<Buffer<uint8_t>>()),
  _bufferPtr(_buffer.get()),
  _start(_bufferPtr->data()),
  _pos(0),
  @@ -110,7 +110,7 @@ class Builder {
  // create an empty Builder, with custom Options
  explicit Builder(Options const* options)
  - : _buffer(new Buffer<uint8_t>()),
  + : _buffer(std::make_shared<Buffer<uint8_t>>()),
  _bufferPtr(_buffer.get()),
  _start(_bufferPtr->data()),
  _pos(0),
  @@ -161,7 +161,7 @@ class Builder {
  ~Builder() {}
  Builder(Builder const& that)
  - : _buffer(new Buffer<uint8_t>(*that._buffer)),
  + : _buffer(std::make_shared<Buffer<uint8_t>>(*that._buffer)),
  _bufferPtr(_buffer.get()),
  _start(_bufferPtr->data()),
  _pos(that._pos),
  @@ -174,7 +174,7 @@ class Builder {
  Builder& operator=(Builder const& that) {
  if (this != &that) {
  - _buffer.reset(new Buffer<uint8_t>(*that._buffer));
  + _buffer = std::make_shared<Buffer<uint8_t>>(*that._buffer);
  _bufferPtr = _buffer.get();
  _start = _bufferPtr->data();
  _pos = that._pos;
  