BOOL, can be read and set, but not unset.

Available infetch

Whether or not streaming miss is enabled for the request. If enabled, Varnish will send the response from the origin to the clients as it is received from origin instead of buffering the entire response first. This can substantially increase the performance of cache misses on large objects.

Try it out

beresp.do_stream is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.

Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.

Push prices or breaking news in real time with Server-Sent-Events

Stream responses to the browser while still receiving data from the origin and also saving it to cache. Great for spreading out server-sent-events streams to millions of users from a single source stream.

Comprehensive logging

Fastly offers a myriad of different variables that you can log. See and test a large collection here.