@Override
  public byte[] get(byte[] key) {
    this.metrics.gets().inc();
    Preconditions.checkArgument(key != null, "Null argument 'key' not allowed");
    byte[] found = this.underlying.get(key);
    if (found != null) {
      metrics.bytesRead().inc(found.length);
    }
    return found;
  }
@param metrics A metrics instance to publish key-value store related statistics
samza-kv-inmemory/src/main/java/org/apache/samza/storage/kv/inmemory/InMemoryKeyValueStore.java