Summary

This PR supersedes #62915 with the same feature work rebased onto current main.

It adds builtin http/https request-body support to network inspection, so Network.getRequestPostData can return text request bodies while preserving the existing rejection behavior for binary request bodies.

It also moves builtin http response-body tracking to a raw-byte hook before IncomingMessage decoding, so response inspection remains correct even when user code calls response.setEncoding(...).

In addition, this PR lets Network.requestWillBeSent carry JS-provided initiator data captured at request construction time. The C++ inspector side validates structured initiator.stack objects against the inspector protocol schema before forwarding them to DevTools.

Problem

Builtin http/https network inspection currently emits request and response lifecycle events, but the builtin client path does not expose request-body bytes to the inspector. As a result, Network.getRequestPostData cannot return POST data for builtin http/https requests.

There are two related gaps:

• IncomingMessage 'data' events are not a stable raw-byte source. If user code calls response.setEncoding('utf8'), chunks observed through userland become strings, while the inspector protocol expects byte-oriented payloads.
• Delaying requestWillBeSent until request-body state is known means a C++ stack captured at emission time would point into Node.js internals rather than the user call site. The initiator needs to be captured when the request is created and validated before being emitted.

Approach

1. Reuse the existing Network.dataSent(...) -> NetworkAgent::getRequestPostData(...) buffering pipeline instead of changing the CDP schema.
2. Add builtin HTTP diagnostics events for request body chunks and request body completion:
   • http.client.request.bodyChunkSent
   • http.client.request.bodySent
3. Capture builtin HTTP response body bytes through a parser-side raw-byte diagnostics event before stream decoding:
   • http.client.response.bodyChunkReceived
4. Defer requestWillBeSent until body state is known, so hasPostData is accurate for both body and body-less requests.
5. Capture the initiator stack in JS at request creation time, pass it through the inspector binding, and validate initiator.stack with generated inspector protocol schema support in C++.
6. Document the new diagnostics channels and message shapes.

Behavior

After this change:

• builtin http and https POST requests with UTF-8 text bodies are available through Network.getRequestPostData
• binary request bodies still reject with the existing inspector error behavior
• builtin http response inspection continues to work even if user code calls response.setEncoding('utf8')
• Network.requestWillBeSent reports accurate hasPostData
• Network.requestWillBeSent can carry JS-captured initiator stack data from the request construction site
• malformed initiator stack input is rejected by C++ schema validation

Tests

This PR adds and extends coverage in:

• test/parallel/test-diagnostics-channel-http.js
• test/parallel/test-inspector-network-http.js
• test/parallel/test-inspector-emit-protocol-event.js
• test/parallel/test-inspector-emit-protocol-event-errors.js

The updated tests cover:

• request body chunk and request body finished diagnostics events
• response body raw-byte diagnostics events
• text request bodies split across write() and end()
• binary request bodies
• http and https Network.getRequestPostData
• binary request-body rejection semantics
• response inspection when the client calls response.setEncoding('utf8')
• accurate hasPostData for body-less requests
• JS-provided initiator stack parsing and forwarding
• malformed initiator stack error handling

Verification

Validated with the targeted test suite:

python3 tools/test.py \
  parallel/test-diagnostics-channel-http \
  parallel/test-inspector-network-http \
  parallel/test-inspector-emit-protocol-event \
  parallel/test-inspector-emit-protocol-event-errors

Also validated manually with an end-to-end inspector run:

./out/Release/node --inspect --experimental-network-inspection ./test.js

Refs

• Replaces inspector,http: support builtin http request bodies #62915
• Refs Tracking issue: Stabilizing network inspection in Node.js #53946