private int getNumberOfEntries() {
      return numberOfEntries(serEntries);
    }
Gets values for all matches for {@code keyToFind} at and in the vicinity of {@code positiveMatchInd}.
@param mmap the serEntries to read values off of
@param keyToFind the needle {@link StoreKey}
@param positiveMatchInd the index of a confirmed positive match
@param totalEntries the total number of entries in the index
@param values the set to which the {@link IndexValue}s will be added
@return a pair consisting of the lowest index that matched the key and the highest
@throws StoreException if there are problems reading from the mmap
ambry-store/src/main/java/com/github/ambry/store/IndexSegment.java