public SELF allowRequestMethods(Iterable<HttpMethod> methods) {
        requireNonNull(methods, "methods");
        final List<HttpMethod> copied = new ArrayList<>();
        Iterables.addAll(copied, methods);
        checkArgument(!copied.isEmpty(), "methods should not be empty.");
        for (int i = 0; i < copied.size(); i++) {
            if (copied.get(i) == null) {
                throw new NullPointerException("methods[" + i + ']');
            }
        }
        allowedRequestMethods.addAll(copied);
        return self();
    }
Specifies the allowed set of HTTP request methods that should be returned in the
CORS {@code "Access-Control-Allow-Methods"} response header.

@param methods the {@link HttpMethod}s that should be allowed.
@return {@code this} to support method chaining.
core/src/main/java/com/linecorp/armeria/server/cors/AbstractCorsPolicyBuilder.java