Help needed: vendor files for Prometheus support

These are the vendor files needed for Prometheus support.
I have not been able to figure out how to do this properly with gopkg.

vendor/github.com/miolini/datacounter/reader.go

@@ -0,0 +1,31 @@
+package datacounter
+
+import (
+	"io"
+	"sync/atomic"
+)
+
+// ReaderCounter is counter for io.Reader
+type ReaderCounter struct {
+	io.Reader
+	count  uint64
+	reader io.Reader
+}
+
+// NewReaderCounter function for create new ReaderCounter
+func NewReaderCounter(r io.Reader) *ReaderCounter {
+	return &ReaderCounter{
+		reader: r,
+	}
+}
+
+func (counter *ReaderCounter) Read(buf []byte) (int, error) {
+	n, err := counter.reader.Read(buf)
+	atomic.AddUint64(&counter.count, uint64(n))
+	return n, err
+}
+
+// Count function return counted bytes
+func (counter *ReaderCounter) Count() uint64 {
+	return atomic.LoadUint64(&counter.count)
+}