To define a storage interface for getOperationStatistics method.
To implement this interface for WiredTiger storage engine.
1. Storage interface could be RecoveryUnit::getOperationStatistics(bool reset)
2. WiredTiger method could be WiredTigerRecoveryUnit::getOperationStatistics(bool reset).
WiredTiger implementation will open a session statistics cursor, fetches the statistics from WiredTiger session and returns them as a BSON object.
Whether this will return the BSON object if any of the statistics is zero ? need to be discussed with NY.