Add a couple more ring optimizations
Add a couple more ring optimizations

Remove some unnecessary delay usages and optimize for
the common case of headers with only a single value.

immutant/immutant,kbaribeau/immutant,coopsource/immutant,immutant/immutant,immutant/immutant,immutant/immutant,coopsource/immutant,coopsource/immutant,kbaribeau/immutant,kbaribeau/immutant