Sets or clears task's check-cancellable flag. If this is true
(the default), then gio.task.Task.propagatePointer, etc, and
gio.task.Task.hadError will check the task's #GCancellable first, and
if it has been cancelled, then they will consider the task to have
returned an "Operation was cancelled" error
(gio.types.IOErrorEnum.Cancelled), regardless of any other error or return
value the task may have had.
If check_cancellable is false, then the #GTask will not check the
cancellable itself, and it is up to task's owner to do this (eg,
via gio.task.Task.returnErrorIfCancelled).
Sets or clears task's check-cancellable flag. If this is true (the default), then gio.task.Task.propagatePointer, etc, and gio.task.Task.hadError will check the task's #GCancellable first, and if it has been cancelled, then they will consider the task to have returned an "Operation was cancelled" error (gio.types.IOErrorEnum.Cancelled), regardless of any other error or return value the task may have had.
If check_cancellable is false, then the #GTask will not check the cancellable itself, and it is up to task's owner to do this (eg, via gio.task.Task.returnErrorIfCancelled).
If you are using gio.task.Task.setReturnOnCancel as well, then you must leave check-cancellable set true.