Currently, we only support Continue and Pause actions, which is quite limiting.

Most notably, we require forwarding HTTP headers before processing HTTP body, which prevents building plugins that perform authorization based on contents of HTTP request body or completely consume requests and generate responses from within plugin (for which proxy_send_local_response is too limited).

Refs:

• Always process HTTP headers before processing HTTP body. proxy-wasm-cpp-host#95
• OnRequestBody not called if onRequestHeaders returns stopIteration proxy-wasm-cpp-host#143
• Can we support FilterHeadersStatus::StopIteration ? proxy-wasm-cpp-host#367
• re support the StopIteration status proxy-wasm-cpp-host#417