EPGStation continues to request streaming even when the program has been canceled

[masnagam]

As a result, EPGStation continues to create garbage recorded data until the program ends or the reservation for the program is removed...

Root cause

EPGStation processes a recording task in the following two steps:

1. prepRecord requests streaming 15 seconds before the program starts. prepRecord awaits streaming data from Mirakurun/mirakc, and then calls doRecord.
2. doRecord returns a promise for recording.

EPGStation stops recording if prepRecord fails in several times. However, EPGStation doesn't stop recording even when streaming in doRecord fails. Therefore, Mirakurun/mirakc have to make prepRecord fail if the program canceled.

Mirakurun doesn't send any data until the program starts. This makes prepRecord fail if the program canceled.

However, mirakc sends PAT packets before the program starts in order to avoid this issue in actix-web. Unfortunately, this workaround makes prepRecord always success.