Created attachment 64335 [details] [review]
patch proposed

A bold statement, I'm sure someone had a good reason for setting it to TRUE (which is also the default for any sink). Also multifdsink sets sync=TRUE. I guess it depends on the type of socket you use (network vs file).

Also better use gst_base_sink_set_sync().

Actually I was the one who ported fdsink to 0.10.0 and the one who chose to set it to TRUE, though I must admit I didn't really know why.
Now I see two reasons why it might be set to FALSE:
First, to do like filesink (which is a bad reason)
Second, I don't really see the point of syncing when you're not playing and most of the time when you'd use fdsink you would pipe the result to another application or to a file and in this case a clock wouldn't really be required.
But you would surely find me wrong so let's close this bug and sorry for the spam.
The way things are is fine by me.

Thing is that changing this now would break the behaviour of applications depending on the default synchronisation.

Added some docs to the plugin to note the default synchronisation behaviour. 

Closing this, the workaround is to manually set the sync to FALSE with the "sync" property when needed.