code: public HttpRequest withBody(byte[] content) {
          headers.set("Content-Length", String.valueOf(content.length));
          // Unpooled.wrappedBuffer(body) allocates ByteBuf from unpooled heap
          return withBody(Flux.defer(() -> Flux.just(Unpooled.wrappedBuffer(content))));
      }
docs: Set the request content.
  The Content-Length header will be set based on the given content's length
  
  @param content the request content
  @return this HttpRequest