v0.101.0

API breaking changes

• Files written by this version of Realm cannot be read by older versions of
  Realm. Existing files will automatically be upgraded when they are opened.

Enhancements

• Greatly improve performance of collection change calculation for complex
  object graphs, especially for ones with cycles.
• NSDate properties now support nanoseconds precision.
• Opening a single Realm file on multiple threads now shares a single memory
  mapping of the file for all threads, significantly reducing the memory
  required to work with large files.
• Crashing while in the middle of a write transaction no longer blocks other
  processes from performing write transactions on the same file.
• Improve the performance of refreshing a Realm (including via autorefresh)
  when there are live Results/RLMResults objects for that Realm.

Bugfixes

• Fix an assertion failure of "!more_before || index >= std::prev(it)->second)"
  in IndexSet::do_add().
• Fix a crash when an RLMArray or List object is destroyed from the wrong
  thread.