@PipelineProperty(
            description = "Specifies Which meta data keys will have their values logged in the send log. A Comma " +
                          "delimited string of keys.",
            defaultValue = META_KEYS_DEFAULT,
            displayPriority = 14)
    public void setLogMetaKeys(final String string) {
        metaKeySet = getMetaKeySet(string);
    }
Handler class that forwards the request to a URL.
stroom-pipeline/src/main/java/stroom/pipeline/writer/HTTPAppender.java