@Override
            protected void doResolve(String hostname, Promise<InetAddress> promise) {
                try {
                    promise.setSuccess(resolver.apply(hostname));
                } catch (Exception e) {
                    promise.setFailure(e);
                }
            }
Creates an {@link AddressResolverGroup} with the specified resolver function.

@param resolver the resolver function which returns an {@link InetAddress} for the given hostname
testing-internal/src/main/java/com/linecorp/armeria/internal/testing/MockAddressResolverGroup.java