Removed unused code.

The threaded streaming code was a research prototype that was
never put to production use. Since development has stopped, I
am removing it. We can always bring it back if there is interest
in further developing it and using it.

Change-Id: If43e4d8e89b35f138c4e294fb6e4643857275dfa
Merge topic 'removed-unused-code' into master

9ad469f1 Removed unused code.