@Override
    public void accept(final METRICS data) {
        final StorageID id = data.id();
        final METRICS existed = buffer.get(id);
        if (existed == null) {
            buffer.put(id, data);
        } else {
            existed.combine(data);
        }
    }
Accept the data into the cache and merge with the existing value.

This method is not thread safe, should avoid concurrency calling.

@param data to be added potentially.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/data/MergableBufferedData.java