func (c *Cmd) Wait() error {
	if c.Process == nil {
		return errors.New("exec: not started")
	}
	if c.finished {
		return errors.New("exec: Wait was already called")
	}
	c.finished = true

	state, err := c.Process.Wait()

	return c.WaitIO(state, err)
}
func (c *Cmd) Wait() error {
	if c.Process == nil {
		return errors.New("exec: not started")
	}
	if c.finished {
		return errors.New("exec: Wait was already called")
	}
	c.finished = true

	state, err := c.Process.Wait()

	return c.WaitIO(state, err)
}
// Wait waits for the command to exit and waits for any copying to
// stdin or copying from stdout or stderr to complete.
//
// The command must have been started by Start.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the command fails to run or doesn't complete successfully, the
// error is of type *ExitError. Other error types may be
// returned for I/O problems.
//
// If c.Stdin is not an *os.File, Wait also waits for the I/O loop
// copying from c.Stdin into the process's standard input
// to complete.
//
// Wait releases any resources associated with the Cmd.