* Renamed range update callbacks
We finally settled on
didEnter/ExitDisplayState
didEnter/ExitPreloadState
didEnter/ExitVisibleState
This change is meant to unify the range update methods to relate to each
other and hopefully be a bit more self explanatory.
* Guarantee interface callbacks happen on main.
* move fetchData / clearFetchedData to default implementations
* Move deprecated methods to new deprecated category
* Don't bring in cocoapod change.
* Nits
* Capetalize
Using Objective-C attributes, in this case `unavailable`, we can hide
unsupported APIs at compile time instead of detecting and warn about it
at runtime with a set of asserts.
Summary:
We observed a deadlock which occurred when two threads were laying out the same set of nodes.
On one thread, layout would occur on a leaf node. It would lock and as part of this layout
process, ASDK walks up the node tree and calls __setNeedsLayout on its supernode until it
reaches the supernode with no supernode. When the supernode gets its call to __setNeedsLayout
it also locks. So leaf node locks and then awaits supernode lock.
On another thread, we're doing a layout pass on the supernode in the above thread. This locks
the supernode and attempts to lock the leaf node. This deadlocks (remember the above thread
is holding onto the leaf lock and awaiting the supernode lock. This thread is holding onto
the supernode lock and awaiting the leaf lock).
This is all exacerbated by the use of recursive locks.
