code: public static void adjustNoChunkedEncoding(ClientRequest request, String requestBody) {
          String fixedLengthString = request.getRequestHeaders().getFirst(Headers.CONTENT_LENGTH);
          String transferEncodingString = request.getRequestHeaders().getLast(Headers.TRANSFER_ENCODING);
          if(transferEncodingString != null) {
              request.getRequestHeaders().remove(Headers.TRANSFER_ENCODING);
          }
          //if already specify a content-length, should use what they provided
          if(fixedLengthString != null && Long.parseLong(fixedLengthString) > 0) {
              return;
          }
          if(!StringUtils.isEmpty(requestBody)) {
              long contentLength = requestBody.getBytes(UTF_8).length;
              request.getRequestHeaders().put(Headers.CONTENT_LENGTH, contentLength);
          }
  
      }
docs: this method is to support sending a server which doesn't support chunked transfer encoding.