https://github.com/whatwg/fetch/pull/419 > Requests with keepalive flag set are allowed to outlive the environment > settings object. We want to make sure that such requests do not > negatively impact the user experience when a page is unloaded, etc. > > This limits the amount of (body) bytes that can be inflight at any point > when the request has the keepalive flag set; this flag is set by > sendBeacon. Expected results: Webkit should support the keepalive flag & enforce the inflight byte limit.