code: @Override public Response intercept(Chain chain) throws IOException {
      final Request request = chain.request();
  
      final Request.Builder builder = request.newBuilder()
          .addHeader(HEADER_NAME, contentType);
  
      if (request.body() != null) {
        rewriteBodyWithCustomContentType(request, builder);
      }
  
      final Request contentTypeRequest = builder.build();
      return chain.proceed(contentTypeRequest);
    }
docs: Method called by framework, to enrich current request with the header information requested.
  
  @param chain the execution chain for the request.
  @return the response received
  @throws IOException if chain had an error