readValue
Returns a BsonValue that is tied to this factory, that represents the same data as value.
This method is useful when you need to convert from a different BsonValue implementation to the one returned by this factory. For example, if you have a BsonValue from the Multiplatform driver and you want to convert it to one from the official driver.
The returned value may be referentially identical to value if value was already produced by this factory.
The returned value may share memory with value.