One last thing worht mentioning. How much a stream is delayed at the start is not an indicator of how big a buffer the client may keep. For instance, Netflix may try to keep a 10 second buffer, but delay playing by only 2 seconds or less. It may backfill after starting, or you may have high enough bandwidth that the first 10 seconds of data (say 50 MB) comes in a second... so it starts playback as soon as it can.
Kind of neat how buffering and TCP packet management hide all of this from the consumer until things go really wrong. This process is happening all the time around us and we don't even know it.

