I’m follow an example from EchoServer.cpp

This isn’t the best medium (pun unintentional) to troubleshoot. Raise an issue here and I will take a look. I’m taking a guess that your _body is empty and you are trying to prepend so pretty confident it’s not a bug with the framework.

One clap, two clap, three clap, forty?

By clapping more or less, you can signal to us which stories really stand out.