Bug 737733 - [IMAPx] Prevent "Stream has outstanding operation" error
Bug 737733 - [IMAPx] Prevent "Stream has outstanding operation" error

...by guarding writes to output streams with a lock, to not write
to the same stream in multiple threads at once.

tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server