@Field
    public void setPrefix(String prefix) {
        //guarantee that the prefix ends with /
        if (!prefix.endsWith("/")) {
            prefix += "/";
        }
        this.prefix = prefix;
    }
prefix to prepend to the fetch key before fetching.
This will automatically add a '/' at the end.

@param prefix
tika-pipes/tika-fetchers/tika-fetcher-s3/src/main/java/org/apache/tika/pipes/fetcher/s3/S3Fetcher.java