public StoreFlushContext createFlushContext(long cacheFlushId, FlushLifeCycleTracker tracker) {
    return new StoreFlusherImpl(cacheFlushId, tracker);
  }
Adds or replaces the specified KeyValues.
<p>
For each KeyValue specified, if a cell with the same row, family, and qualifier exists in
MemStore, it will be replaced. Otherwise, it will just be inserted to MemStore.
<p>
This operation is atomic on each KeyValue (row/family/qualifier) but not necessarily atomic
across all of them.
@param readpoint readpoint below which we can safely remove duplicate KVs
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HStore.java