static <T, U> Attributes of(AttributeKey<T> k1, T v1, AttributeKey<U> k2, U v2) {
        return builder().set(k1, v1)
                        .set(k2, v2)
                        .build();
    }
Returns a new {@link Attributes} with the specified pairs of an {@link AttributeKey} and a {@code value}.
core/src/main/java/com/linecorp/armeria/common/Attributes.java