@Override
    public void checkInitialization(InitializableProblemHandler problemHandler) throws TikaConfigException {
        super.checkInitialization(problemHandler);
        mustNotBeEmpty("bucket", this.bucket);
        mustNotBeEmpty("projectId", this.projectId);
    }
This initializes the gcs client.

@param params params to use for initialization
@throws TikaConfigException
tika-pipes/tika-pipes-iterators/tika-pipes-iterator-gcs/src/main/java/org/apache/tika/pipes/pipesiterator/gcs/GCSPipesIterator.java