Puller: refactor + use Task API

* drop rx byte count functionality
* will be re-added to Task as necessary

refs #10

util/io.go

@@ -3,7 +3,6 @@ package util
 import (
 	"io"
 	"os"
-	"time"
 )
 
 type ReadWriteCloserLogger struct {
@@ -97,52 +96,3 @@ func (c *ChainedReader) Read(buf []byte) (n int, err error) {
 
 	return
 }
-
-type IOProgress struct {
-	TotalRX uint64
-}
-
-type IOProgressCallback func(progress IOProgress)
-
-type IOProgressWatcher struct {
-	Reader         io.Reader
-	callback       IOProgressCallback
-	callbackTicker *time.Ticker
-	progress       IOProgress
-	updateChannel  chan int
-}
-
-func (w *IOProgressWatcher) KickOff(callbackInterval time.Duration, callback IOProgressCallback) {
-	w.callback = callback
-	w.callbackTicker = time.NewTicker(callbackInterval)
-	w.updateChannel = make(chan int)
-	go func() {
-	outer:
-		for {
-			select {
-			case newBytes, more := <-w.updateChannel:
-				w.progress.TotalRX += uint64(newBytes)
-				if !more {
-					w.callbackTicker.Stop()
-					break outer
-				}
-			case <-w.callbackTicker.C:
-				w.callback(w.progress)
-			}
-		}
-		w.callback(w.progress)
-	}()
-}
-
-func (w *IOProgressWatcher) Progress() IOProgress {
-	return w.progress
-}
-
-func (w *IOProgressWatcher) Read(p []byte) (n int, err error) {
-	n, err = w.Reader.Read(p)
-	w.updateChannel <- n
-	if err != nil {
-		close(w.updateChannel)
-	}
-	return
-}