At the beginning of every segment there was a drop to Unknown speed due to timeslice being too small to calculate speed.
Now last speed from the previous fragment is used.
state['eta'] = self.calc_eta(
start, time_now, estimated_size,
state['downloaded_bytes'])
- state['speed'] = s.get('speed')
+ state['speed'] = s.get('speed') or ctx.get('speed')
+ ctx['speed'] = state['speed']
ctx['prev_frag_downloaded_bytes'] = frag_downloaded_bytes
self._hook_progress(state)