diff --git a/lib/restclient/payload.rb b/lib/restclient/payload.rb
index fe6adfa..5112f33 100644
--- a/lib/restclient/payload.rb
+++ b/lib/restclient/payload.rb
@@ -144,7 +144,7 @@ module RestClient
       def build_stream(params)
         b = '--' + boundary
 
-        @stream = Tempfile.new("RESTClient.Stream.#{rand(1000)}")
+        @stream = Tempfile.new('rest-client.multipart.')
         @stream.binmode
         @stream.write(b + EOL)