}
                else if ( last == null ) {
                    // don't have enough credits/space for the first request, block until available
                    // for space there is nothing we can do, callers need to make sure that a single message fits

                    try {
                        long timeout = getResponseTimeout(chain);
                        if ( params.contains(RequestParam.NO_TIMEOUT) ) {

                // referrals.
                try ( SmbTreeHandleImpl th = ensureTreeConnected() ) {
                    if ( this.fileLocator.getType() == TYPE_SHARE ) {
                        // treeConnect is good enough, but we need to do this after resolving DFS
                        try ( SmbTreeHandleImpl th2 = ensureTreeConnected() ) {}
                    }
                    else {

                        byte[] signingKey = npa.getSigningKey(getContext(), negoResp.getServerData().encryptionKey);
                        if ( signingKey == null ) {
                            throw new SmbException("Need a signature key but the server did not provide one");
                        }
                        request.setDigest(new SMB1SigningDigest(signingKey, false));
                    }
                }