Ruby-ldap: @sasl_quiet?

Ok, it seems that every time I create an LDAP::Conn object I get this

    warning: instance variable @sasl_quiet not initialized

So how do I initialize it? I’m getting the warning from the
constructor, which
according to the RDoc has only two arguments. The first thing I do after
construction is call conn.sasl_quiet = true, but by then it’s too late.