public static Integer execute(InternalPool pool, String region) {
    AbstractOp op = new SizeOpImpl(region);
    return (Integer) pool.execute(op);
  }
Does a region size on a server using connections from the given pool to communicate with the
server.

@param pool the pool to use to communicate with the server.
@param region the name of the region to do the entry keySet on
geode-core/src/main/java/org/apache/geode/cache/client/internal/SizeOp.java