Documentation for method
bind-stderr assembled from the following types:
method bind-stderr(IO::Handle )
STDERR of the target process to a handle (which must be opened). If
STDERR is closed X::Proc::Async::BindOrUse will be thrown.
my = Proc::Async.new("ls", "--foo", :err);my = "ls.err".IO.open(:w);.bind-stderr();.start;