Support simultaneous use of the MBVariableSpace from multiple threads #4
Description
To avoid the overhead of thread synchronization schemes, it's been a long-running decision to restrict the use of Mockingbird expressions to the main thread, and the same goes for the MBVariableSpace instance.
Much has changed since the last time we investigated this, and there are new GCD-based thread synchronization mechanisms that have lower overhead.
Can we add multi-threaded support without affecting performance too drastically on apps that are heavy users of expressions?
We should create a concurrency branch and experiment with this. It would be great to be able to have thread locking handled at the platform level.