never block in notify_caller, BugzID 10096

diff --git a/src/rexi_server.erl b/src/rexi_server.erl
index 6f8b864..1589ba3 100644
--- a/src/rexi_server.erl
+++ b/src/rexi_server.erl
@@ -69,4 +69,4 @@
     lists:keyfind(Ref, 2, List).
 
 notify_caller({Caller, Ref}, Reason) ->
-    erlang:send(Caller, {rexi_EXIT, Ref, Reason}).
+    spawn(erlang, send, [Caller, {rexi_EXIT, Ref, Reason}]).