context should have access to the locked element.

[vmpstr]

Particularly in lock-before-append mode, it seems to always be necessary to have access to the locked element, and this pattern is probably very likely:

e.acquireDisplayLock((context) => { func(context, e); });

Maybe |context| should have a lockedElement member so that one can write:

e.acquireDisplayLock(func);

And then context.lockedElement.appendChild(...); or whatever else is needed.

WDYT?

[chrishtr]

Seems reasonable to me to put in the API.