* Implementations must quickly dispatch callbacks to avoid creating a bottleneck.
 *
 * While [onReset] may occur at any time, the following callbacks are expected in order,
 * correlated by stream ID.
 *
 *  * [onRequest]
 *  * [onHeaders] (unless canceled)
 *  * [onData] (optional sequence of data frames)
 *

| `Traceparent` | (Experimental) This maintains tracing information. Note this is tracing of *connections*, and is not correlated to tracing of user's own HTTP requests. However, this is useful to follow a connection across ztunnels.                                 |

## Traffic routing