public SELF preflightResponseHeader(CharSequence name, Object... values) {
        requireNonNull(name, "name");
        requireNonNull(values, "values");
        checkArgument(values.length > 0, "values should not be empty.");
        for (int i = 0; i < values.length; i++) {
            if (values[i] == null) {
                throw new NullPointerException("values[" + i + ']');
            }
        }
        preflightResponseHeaders.put(HttpHeaderNames.of(name),
                                     new ConstantValueSupplier(ImmutableList.copyOf(values)));
        return self();
    }
Specifies 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.

@param name the name of the HTTP header.
@param values the values for the HTTP header.
@return {@code this} to support method chaining.
core/src/main/java/com/linecorp/armeria/server/cors/AbstractCorsPolicyBuilder.java