Prevent body from being closed by the Request RoundTripper

requests.go

@@ -14,6 +14,15 @@ func (c *Client) req(method, path string, body io.Reader, intercept func(*http.R
 	var retryBuf io.Reader
 
 	if body != nil {
+		// Because Request#Do closes closable streams, Seeker#Seek
+		// will fail on retry because stream is already  closed.
+		// This inhibits the closing of the passed stream on passing
+		// it to the RoundTripper and closes the stream after we
+		// are done with the body content.
+		if cl, ok := body.(io.Closer); ok {
+			body = closeInhibitor{body}
+			defer cl.Close()
+		}
 		// If the authorization fails, we will need to restart reading
 		// from the passed body stream.
 		// When body is seekable, use seek to reset the streams

utils.go

@@ -133,3 +133,14 @@ func (l *limitedReadCloser) Read(buf []byte) (int, error) {
 func (l *limitedReadCloser) Close() error {
 	return l.rc.Close()
 }
+
+// closeInhibitor implements io.Closer and
+// wraps a Reader. When Close() is performed
+// on it, it will simply be silently rejected.
+type closeInhibitor struct {
+	io.Reader
+}
+
+func (ci closeInhibitor) Close() error {
+	return nil
+}