public String toString () {
        String c;
        switch ( this.command ) {

        case SMB2_NEGOTIATE:
            c = "SMB2_NEGOTIATE";
            break;
        case SMB2_SESSION_SETUP:
            c = "SMB2_SESSION_SETUP";
            break;
        case SMB2_LOGOFF:
            c = "SMB2_LOGOFF";
            break;
        case SMB2_TREE_CONNECT:
            c = "SMB2_TREE_CONNECT";