The ETag cache key for a request: its URL, scoped to the identity ESI has
accepted and to the client settings that vary ESI's answer. Reads that serve an entry without a request, and writes of what
ESI answered, use this key.
Once a request has been sent, authorizationHeader is the header it
carried: a concurrent request may have replaced the client's token in the
meantime, and what ESI answered belongs to the token that asked, not to
the one the client holds when the answer arrives.
The ETag cache key for a request: its URL, scoped to the identity ESI has accepted and to the client settings that vary ESI's answer. Reads that serve an entry without a request, and writes of what ESI answered, use this key.
Once a request has been sent,
authorizationHeaderis the header it carried: a concurrent request may have replaced the client's token in the meantime, and what ESI answered belongs to the token that asked, not to the one the client holds when the answer arrives.