reader.go | 5 ++++-

diff --git a/reader.go b/reader.go
index 4689bc64e563d3babea39a0e27e6f730fcabe638..1b3815f3bdc6a77fa8330f09131131316eda3e11 100644
--- a/reader.go
+++ b/reader.go
@@ -34,8 +34,11 @@ // Configure the number of bytes ahead of a read that should also be
 // prioritized in preparation for further reads.
 func (r *Reader) SetReadahead(readahead int64) {
 	r.mu.Lock()
-	defer r.mu.Unlock()
 	r.readahead = readahead
+	r.mu.Unlock()
+	r.t.cl.mu.Lock()
+	defer r.t.cl.mu.Unlock()
+	r.tickleClient()
 }
 
 func (r *Reader) readable(off int64) (ret bool) {