* feat: limit protocol streams per-connection
Uses the `maxInboundStreams` and `maxOutboundStreams` of the `registrar.handle`
opts to limit the number of concurrent streams open on each connection
on a per-protocol basis.
Both values default to 1 so some tuning will be necessary to set
appropriate values for some protocols.
* chore: make error codes consistent
* chore: fix up examples
de30c2cec7