Hi,it appears to me that this header replicates something that is already there; just use the last event ID as etag, and then you can do something like:
GET /foobar HTTP/1.1 If-None-Match: "abc"Note that this makes If-None-Match a request header on which the response varies, thus it should carry:
Vary: If-None-Match ...but this is the case for Last-Event-ID as well. Best regards, Julian
