Increase ssh tunnel's kChunkSize for faster reads
Increase ssh tunnel's kChunkSize for faster reads

This greatly reduces the hangs we are sometimes seeing on capture
stop. The real cause is really the fact that the tunnel is updated
on the ui thread, which shouldn't be the case as it is susceptible
to being drastically delayed by a long render frame.

See b/172686811.
google/orbit,google/orbit,google/orbit,google/orbit