During a chunk migration of a sharded time-series collections, we clear all the open buckets on the source shard. This seems to have an impact on the write throughput. One of the suggested ways to improve the performance was to clear only the buckets that match the current chunk range that is being migrated.

To achieve this, we need an alternative interface to BucketCatalog::clear(const NamespaceString& ns) which can accepts a start and end values of a shard key pattern and clear only the overlapping buckets. Note that this function is called in the critical section. So it is also important that this implementation does not iterator over all the open buckets to identify the overlapping buckets.