public RequestBody convert(T value) throws IOException {
            try {
                byte[] content = JSON.toJSONBytesWithFastJsonConfig(fastJsonConfig.getCharset()
                        , value
                        , fastJsonConfig.getSerializeConfig()
                        , fastJsonConfig.getSerializeFilters()
                        , fastJsonConfig.getDateFormat()
                        , JSON.DEFAULT_GENERATE_FEATURE
                        , fastJsonConfig.getSerializerFeatures()
                );
                return RequestBody.create(MEDIA_TYPE, content);
            } catch (Exception e) {
                throw new IOException("Could not write JSON: " + e.getMessage(), e);
            }
        }
Sets serializer features.

@param features the features
@return the serializer features
@see FastJsonConfig#setSerializerFeatures(SerializerFeature...)
@deprecated
src/main/java/com/alibaba/fastjson/support/retrofit/Retrofit2ConverterFactory.java