after set http body to json strings,I want to get json string from HTTPServerResponse& response ,how to write code？

[edidada]

Is your feature request related to a problem? Please describe.
after set http body to json strings,I want to get json string from HTTPServerResponse& response ,how to write code？

Describe the solution you'd like

Describe alternatives you've considered

thread_local std::string tls_resp_json_body = "";//define

    tls_resp_json_body = json_body;//set
    std::string responseStr = tls_resp_json_body;//get

Additional context

[matejk]

In what way is this related to Poco?