private Builder annotationType(Class<? extends Annotation> annotationType) {
            assert annotationType == Param.class ||
                   annotationType == Attribute.class ||
                   annotationType == Header.class ||
                   annotationType == RequestObject.class : annotationType.getSimpleName();
            this.annotationType = annotationType;
            return this;
        }
Sets the annotation which is one of {@link Param}, {@link Header} or {@link RequestObject}.
core/src/main/java/com/linecorp/armeria/internal/server/annotation/AnnotatedValueResolver.java