revokeToken method
Makes token invalid, as revoking a key does on a real server: every
open connection bound to it loses its subscriptions (closed for each)
and its session (authed with rejected, unasked).
Implementation
void revokeToken(String token) {
_tokens.remove(token);
for (final connection in openConnections.toList()) {
if (connection.token != token) continue;
_bind(connection, null, null);
connection.send(const DwAuthenticatedMessage.rejected());
}
}