Make sure it's safe to call bufferedPercent before the SWF loads

[dmlap]

Manual time tracking calles bufferedPercent() on an interval and doesn't wait for the tech to be ready. If it's called before the SWF is loaded, it will throw an error. Make sure the methods required by bufferedPercent() don't throw if they're called early. Fixes #2288.

[gkatsev]

LGTM

[heff]

lgtm. Should we just wrap every swf property call with a function that does this?

[dmlap]

After writing this commit, I wondered if it would be better to just wait for tech ready to start manual time tracking.

@heff the only downside of that is we have to figure out a reasonable "default" value for each property, which isn't totally obvious (e.g. attributes that return Time Ranges, for instance).

[heff]

Ah, yeah, manual time tracking should definitely be waiting for tech ready. Though it doesn't hurt to also have this added protection built in. Do you want to add the former first or just move forward with this? Looks good to me either way.

[dmlap]

I'm ok with moving forward with this for now. I can file an issue to fix the latter so we don't forget about it.

[dmlap]

I can't help but note this sort of problem wouldn't exist if the base tech handled behavior before the official ready event.

[heff]

Yeah, I don't think anyone's arguing that's not a better direction, but what do you mean by the base tech? Should we try to make Tech handle all the defaults?

[dmlap]

Decided to implement the more comprehensive fix in #2316, so I'm closing this.

@heff I was thinking of Tech providing a basic implementation until the ready event fires, along the lines of what we were discussing to fix the async startup issues with the DASH source handler.

[heff]

@dmlap #2316 is against master while this was against stable. Did we still want to get a patch out with this fix, or no?

[gkatsev]

LGTM