=begin pod

=TITLE class X::Proc::Async::AlreadyStarted

=SUBTITLE Error due to calling C<start> on an already started L<Proc::Async> object

    class X::Proc::Async::AlreadyStarted is Exception {}

When you call C<start> twice on the same L<Proc::Async|/type/Proc::Async>
object, the second invocation will die with an
C<X::Proc::Async::AlreadyStarted> exception.

    my $proc = Proc::Async.new("echo");
    $proc.start;
    $proc.start;
    CATCH { default { put .^name, ': ', .Str } };
    # OUTPUT: «X::Proc::Async::AlreadyStarted: Process has already been started␤»

=end pod
