fix bug : should drain channel of timer after stop

[ikenchina]

Ensure the channel is empty after a call to Stop.

Changes

Drain channel.

Verification

Document of go Timer notices that : To ensure the channel is empty after a call to Stop, check the // return value and drain the channel.

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[ikenchina]

update

[johanbrandhorst]

Have you been able to sign the CLA?

[ikenchina]

Yes

[johanbrandhorst]

Thanks for your contribution!

[ash2k]

The timer is discarded after this use, it doesn't matter if the channel has a value or not. No need to drain it :)