@Field
    public void setFileExtension(String fileExtension) {
        this.fileExtension = fileExtension;
    }
If you want to customize the output file's file extension.
Do not include the "."

@param fileExtension
tika-pipes/tika-emitters/tika-emitter-s3/src/main/java/org/apache/tika/pipes/emitter/s3/S3Emitter.java