StringBuilders#reusableBuilder(int expectedSize)

[jontejj]

• This feature would greatly minimize the need to allocate/deallocate memory for large strings
• Reusing StringBuilders using a ThreadLocal<List> perhaps, or a ConcurrentSkipListMap?
• Callers must free the StringBuilder when they're done.
• Freed builders must be evicted from the cache after some time to avoid memory leaks