The lack of documentation is problematic when learning how to use MongoDB and the driver. I found myself reading the source code instead of the documentation to figure out crucial things such as:

Which methods are safe to call across different threads?

• What objects can be passed between threads?

• Which methods throw exceptions, and why?

• Which objects represent ownership? The distinction between value/view on the bsoncxx side suggests awareness of this, but was hard to figure out for other objects, such as client, connection, pool, transaction, etc.