public static boolean isJson(String mediaType) {
        MediaType type = from(mediaType);
        return (type.getType().equals("application") && type.getSubtypeWithoutSuffix().equals("json"))
                || type.getSuffix().filter(s -> s.equals("json")).isPresent();
    }
Detects if the given media type string is JSON, meaning it
is "application/json" or uses the "+json" structured syntax
suffix.

@param mediaType Media type to parse and test if it's JSON.
@return Returns true if the given media type is JSON.
smithy-utils/src/main/java/software/amazon/smithy/utils/MediaType.java