message: Output getters do not need mutable access
diff: @@ -169,12 +169,12 @@ impl Output {
  }
  /// Grab the stdout of the process.
  - fn stdout(&mut self) -> Shared<Bytes> {
  + fn stdout(&self) -> Shared<Bytes> {
  self.stdout.clone()
  }
  /// Grab the stderr of the process.
  - fn stderr(&mut self) -> Shared<Bytes> {
  + fn stderr(&self) -> Shared<Bytes> {
  self.stderr.clone()
  }
  }
  