@Override
    public void checkInitialization(InitializableProblemHandler problemHandler) throws TikaConfigException {
        mustNotBeEmpty("bucket", this.bucket);
        mustNotBeEmpty("region", this.region);
    }
This initializes the s3 client. Note, we wrap S3's RuntimeExceptions,
e.g. AmazonClientException in a TikaConfigException.

@param params params to use for initialization
@throws TikaConfigException
tika-pipes/tika-emitters/tika-emitter-s3/src/main/java/org/apache/tika/pipes/emitter/s3/S3Emitter.java