The embedder requires that the isolate is unpaused, because the runInView method requires interaction with dart engine APIs that are not thread-safe. These APIs must be run on the same thread that would be blocked by the pause. Simply unpausing is not sufficient, because this does not prevent the isolate from immediately hitting a breakpoint, for example if the breakpoint was placed in a loop or in a frequently called method. Instead, all breakpoints are first disabled and then the isolate resumed.