test.js

var toServer = csp.chan();
var throttled = throttle(toServer);

csp.go(function* () {
    var msg;
    while (true) {
        msg = yield csp.take(toServer);
        if (msg === csp.CLOSED) { return; }
        
        console.log(msg);
    }
});

csp.go(function* () {
    for (var i = 0; i < 10; i++) {
        yield csp.put(throttled, 'foo ' + i);
    }
});

throttle.js

function throttle(outCh, opts) {
    opts = opts || { };
    
    var delay = opts.hasOwnProperty('delay') ? opts.delay : 2000,
        burstLines = opts.hasOwnProperty('burstLines') ? opts.burstLines : 5,
        burst = opts.hasOwnProperty('burst') ? opts.burst : burstLines * delay,
        limit = opts.hasOwnProperty('limit') ? opts.limit : 10,
        nextMessage = Date.now();
    
    var inCh = csp.chan(csp.buffers.dropping(limit));
    
    csp.go(function* () {
        while (true) {
            var msg = yield csp.take(inCh);

            if (msg === csp.CLOSED) {
                outCh.close();
                return;
            }
            
            var now = Date.now();
            
            if (nextMessage < now) { nextMessage = now; }
            nextMessage += delay;
            
            if (nextMessage >= now + burst) {
                yield csp.timeout(nextMessage - now - burst);
            }

            csp.put(outCh, msg);
        }
    });
    
    return inCh;
}