question: public static RawHeaders fromMultimap ( Map < String , List < String > > map , boolean response ) throws IOException { if ( ! response ) throw new UnsupportedOperationException ( ) ; RawHeaders result = new RawHeaders ( ) ; for ( Entry < String , List < String > > entry : map . entrySet ( ) ) { String fieldName = entry . getKey ( ) ; List < String > values = entry . getValue ( ) ; if ( fieldName != null ) { for ( String value : values ) { result . addLenient ( fieldName , value ) ; } } else if ( ! values . isEmpty ( ) ) { result . setStatusLine ( values . get ( values . size ( ) - 1 ) ) ; } } return result ; }
target:  Creates a new instance from the given map of fields to values. If present, the null field's last element will be used to set the status line.