public DocumentProcessingHandlerParameters setMetric(Metric metric) {
        this.metric = metric;
        return this;
    }
Class to hold parameters given to DocumentProcessingHandler, typically used by unit tests.

@author Einar M R Rosenvinge
@see com.yahoo.docproc.jdisc.DocumentProcessingHandler
docproc/src/main/java/com/yahoo/docproc/jdisc/DocumentProcessingHandlerParameters.java