public void setFilterThreshold(double threshold) {
        verifyThat(this.filterThreshold == null, "already has filter-threshold");
        verifyThat(threshold >= 0.0 && threshold <= 1.0, "filter-threshold must be in range [0, 1]");
        this.filterThreshold = threshold;
    }
This class holds the extracted information after parsing a
rank-profile block in a schema (.sd) file, using simple data
structures as far as possible.  Do not put advanced logic here!

@author arnej27959
config-model/src/main/java/com/yahoo/schema/parser/ParsedRankProfile.java