Apply a non-ACK SETTINGS frame from the peer and emit a SETTINGS-ACK. Also adjusts every outbound stream window by the delta between the old and new SETTINGS_INITIAL_WINDOW_SIZE (RFC 7540 §6.9.2).

Build a synthetic stream-1 from the original h2c upgrade request and dispatch it to the webpart. RFC 7540 §3.2: stream 1 is implicitly half-closed from the client toward the server (the request body has been fully delivered as the HTTP/1.1 upgrade request).

Read the next frame as (header, raw payload bytes), without invoking a per-type decoder. The dispatcher runs `validateFrame` against the raw form first so that malformed inputs surface as proper GOAWAY/RST_STREAM frames instead of asserting inside a decoder.

Reset a single stream with the given error code. Stream-level failures don't tear down the connection.

Top-level entry point used by the h2c upgrade handler. Runs the connection preface, optionally dispatches a seeded upgrade request on stream 1, then enters the read/dispatch loop until the connection is closed.

Top-level entry point used by the HTTP/2 prior-knowledge handler. The request-line portion of the preface has already been consumed by the HTTP/1.1 request-line reader; this runs the rest of the preface exchange and then enters the read/dispatch loop until the connection is closed.

Read frames in a loop, dispatching each to `handleFrame`, until either our connection is torn down (GOAWAY sent/received) or the transport reports an error. Returns when the loop terminates so the caller can recycle the connection.

Send a connection-level GOAWAY and stop the read loop. Idempotent.

 Run the HTTP/2 connection-preface exchange (RFC 7540 §3.5):
   * read the 24-byte client preface ("PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n")
   * send our own (potentially empty) SETTINGS frame as the server
     connection preface

Run the HTTP/2 connection-preface exchange for prior-knowledge mode (RFC 7540 §3.4). The caller has already consumed the first 16 bytes of the 24-byte preface as an HTTP/1.1-looking request line ("PRI * HTTP/2.0\r\n") via the normal request-line reader. This method reads the remaining 8 preface bytes ("\r\nSM\r\n\r\n") and sends our own (potentially empty) SETTINGS frame as the server connection preface.

Write a single HTTP/2 response (HEADERS + 0..n DATA + optional trailing HEADERS) on `streamId`, respecting `peerSettings.maxFrameSize` and the outbound flow-control windows. Setting trailers via `Trailers.set` on the response context is honoured: when present, the final DATA frame does NOT set END_STREAM and a trailing HEADERS frame with END_STREAM is emitted after the body.