(make-bridge xmit recv) -> bridge
Creates a bridge using two channels.
Example Usage:
(define west-to-east (make-channel))
(define east-to-west (make-channel))
(define west-bridge (make-bridge (output-chain west-to-east
(trace-filter "west "))
east-to-west))
(define east-bridge (make-bridge (output-chain east-to-west
(trace-filter " east"))