question: public CorsServiceBuilder preflightResponseHeader ( final AsciiString name , final Object ... values ) { requireNonNull ( name , "name" ) ; requireNonNull ( values , "values" ) ; for ( int i = 0 ; i < values . length ; i ++ ) { if ( values [ i ] == null ) { throw new NullPointerException ( "values[" + i + ']' ) ; } } if ( values . length == 1 ) { preflightResponseHeaders . put ( name , new ConstantValueSupplier ( values [ 0 ] ) ) ; } else { preflightResponseHeader ( name , Arrays . asList ( values ) ) ; } return this ; }
target:  Returns HTTP response headers that should be added to a CORS preflight response. <p>An intermediary like a load balancer might require that a CORS preflight request have certain headers set. This enables such headers to be added.