gistfile1.go

func buffer(in <-chan T) <-chan T {
out := make(chan T)
go func() {
var buf = list.New()
for {
outc := out
var v T
if buf.Len() == 0 {
// buffer empty: don't try to send on output
if in == nil {
close(out)
return
}
outc = nil
}else{
v = buf.Front().Value.(T)
}
select {
case e := <-in:
if closed(in) {
in = nil
} else {
buf.PushBack(e)
}
case outc <- v:
buf.Remove(buf.Front())
}
}
}()
return out
}