Added new events broadcast_starting, broadcast_started, broadcase_start_failed

[dcmouser]

Added new events triggered by Go Live functionality in OBS for starting broadcasts on YouTube.

Description

Just a couple of new events to match the new GoLive button in OBS that transitions stream between streaming and actually going live.

Motivation and Context

These events can be very useful for script to know when the stream has actually gone live (as opposed to when streaming was started, which may have happened many minutes before). These events are particularly useful for calculating timestamps on YouTube.

How Has This Been Tested?

Tested on windows OBS version 27 and 28.

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[norihiro]

Description should be added to the docs/sphinx/reference-frontend-api.rst.

[dcmouser]

Added documentation to docs/sphinx/reference-frontend-api.rst as suggested.

[cg2121]

There should probably be a stopping and stopped event as well, as the streaming and recording events have these, so we are consistent.

[dcmouser]

"There should probably be a stopping and stopped event as well, as the streaming and recording events have these, so we are consistent." <-- This would make intuitive sense, but it felt to me that there wasn't any real difference between stopping a broadcast and stopping streaming. Unlike the starting case, where broadcast can start much later than streaming, in the broadcasting case, when you stop broadcasting you stop streaming (as far as i can tell). However I would be happy to add the BroadcastStopping and BroadcastStopped events if that was the only thing holding up this code.

[PatTheMav]

I agree that if events specific to a broadcast lifecycle are added that we should add all of them (and not just the ones related to starting a broadcast).