text: public static TermGroupFacetCollector CreateTermGroupFacetCollector(string groupField,string facetField,bool facetFieldMultivalued,BytesRef facetPrefix,int initialSize){if (facetFieldMultivalued){return new MV(groupField, facetField, facetPrefix, initialSize);}else{return new SV(groupField, facetField, facetPrefix, initialSize);}}