How to use the apio.util.AsyncPipe function in apio

default.update(kwargs)
    kwargs = default

    try:
        p = subprocess.Popen(*args, **kwargs)
        result['out'], result['err'] = p.communicate()
        result['returncode'] = p.returncode
    except KeyboardInterrupt:
        click.secho('Aborted by user', fg='red')
        exit(1)
    except Exception as e:
        click.secho(str(e), fg='red')
        exit(1)
    finally:
        for s in ('stdout', 'stderr'):
            if isinstance(kwargs[s], AsyncPipe):
                kwargs[s].close()

    _parse_result(kwargs, result)

    return result

system_base_dir = util.get_package_dir('tools-system')
        system_bin_dir = util.safe_join(system_base_dir, 'bin')

        on_stdout = None if silent else self._on_stdout
        on_stderr = self._on_stderr

        if util.check_package(
            self.name,
            self.version,
            self.spec_version,
            system_bin_dir
        ):
            result = util.exec_command(
                util.safe_join(system_bin_dir, command + self.ext),
                stdout=util.AsyncPipe(on_stdout),
                stderr=util.AsyncPipe(on_stderr))

        return result

processing_board = board
            else:
                processing_board = 'custom board'
            click.echo('[%s] Processing %s' % (
                datetime.datetime.now().strftime('%c'),
                click.style(processing_board, fg='cyan', bold=True)))
            click.secho('-' * terminal_width, bold=True)

        if self.profile.get_verbose_mode() > 0:
            click.secho('Executing: {}'.format(
                ' '.join(util.scons_command + ['-Q', command] + variables)))

        result = util.exec_command(
            util.scons_command + ['-Q', command] + variables,
            stdout=util.AsyncPipe(self._on_stdout),
            stderr=util.AsyncPipe(self._on_stderr)
        )

        # -- Print result
        exit_code = result.get('returncode')
        is_error = exit_code != 0
        summary_text = ' Took %.2f seconds ' % (time.time() - start_time)
        half_line = '=' * int(
            ((terminal_width - len(summary_text) - 10) / 2))
        click.echo('%s [%s]%s%s' % (
            half_line,
            (click.style(' ERROR ', fg='red', bold=True)
             if is_error else click.style('SUCCESS', fg='green', bold=True)),
            summary_text,
            half_line
        ), err=is_error)

result = {}
        system_base_dir = util.get_package_dir('tools-system')
        system_bin_dir = util.safe_join(system_base_dir, 'bin')

        on_stdout = None if silent else self._on_stdout
        on_stderr = self._on_stderr

        if util.check_package(
            self.name,
            self.version,
            self.spec_version,
            system_bin_dir
        ):
            result = util.exec_command(
                util.safe_join(system_bin_dir, command + self.ext),
                stdout=util.AsyncPipe(on_stdout),
                stderr=util.AsyncPipe(on_stderr))

        return result

if board:
                processing_board = board
            else:
                processing_board = 'custom board'
            click.echo('[%s] Processing %s' % (
                datetime.datetime.now().strftime('%c'),
                click.style(processing_board, fg='cyan', bold=True)))
            click.secho('-' * terminal_width, bold=True)

        if self.profile.get_verbose_mode() > 0:
            click.secho('Executing: {}'.format(
                ' '.join(util.scons_command + ['-Q', command] + variables)))

        result = util.exec_command(
            util.scons_command + ['-Q', command] + variables,
            stdout=util.AsyncPipe(self._on_stdout),
            stderr=util.AsyncPipe(self._on_stderr)
        )

        # -- Print result
        exit_code = result.get('returncode')
        is_error = exit_code != 0
        summary_text = ' Took %.2f seconds ' % (time.time() - start_time)
        half_line = '=' * int(
            ((terminal_width - len(summary_text) - 10) / 2))
        click.echo('%s [%s]%s%s' % (
            half_line,
            (click.style(' ERROR ', fg='red', bold=True)
             if is_error else click.style('SUCCESS', fg='green', bold=True)),
            summary_text,
            half_line
        ), err=is_error)