@Override
    public ExchangeType exchangeType(RoutingContext routingContext) {
        // Response stream will be supported via WebSocket.
        final MediaType contentType = routingContext.contentType();
        if (contentType != null && contentType.is(MediaType.MULTIPART_FORM_DATA)) {
            return ExchangeType.REQUEST_STREAMING;
        }
        return ExchangeType.UNARY;
    }
Should not use {@link JacksonUtil#newDefaultObjectMapper()} that will convert a JSON object into
`scala.Map` if a `jackson-module-scala` module is registered.
graphql-protocol/src/main/java/com/linecorp/armeria/server/graphql/protocol/AbstractGraphqlService.java