diff --git a/lib/pure/asyncftpclient.nim b/lib/pure/asyncftpclient.nim
index 208782c056..ba565059dd 100644
--- a/lib/pure/asyncftpclient.nim
+++ b/lib/pure/asyncftpclient.nim
@@ -63,7 +63,7 @@
 ##    import asyncdispatch, asyncftpclient
 ##
 ##    proc onProgressChanged(total, progress: BiggestInt,
-##                            speed: float): Future[void] =
+##                            speed: float) {.async.} =
 ##      echo("Uploaded ", progress, " of ", total, " bytes")
 ##      echo("Current speed: ", speed, " kb/s")
 ##