code: public ByteBuffer createLocal(long count)
      {
          ContextState state = ContextState.allocate(0, 1, 0);
          state.writeLocal(CounterId.getLocalId(), 1L, count);
          return state.context;
      }
docs: Creates a counter context with a single local shard.
  For use by tests of compatibility with pre-2.1 counters only.