anchor.diff:    /**
      * No exceptions are raised, even for network issues.
      */
  -  static const ERRORS_IGNORED = const WriteConcern(w: -1, wtimeout: 0, fsync: false, j:false);
  +  static const ERRORS_IGNORED =
  +      const WriteConcern(w: -1, wtimeout: 0, fsync: false, j: false);
   
     /**
      * Write operations that use this write concern will return as soon as the message is written to the socket.
      * Exceptions are raised for network issues, but not server errors.
      */
  -  static const UNACKNOWLEDGED = const WriteConcern(w: 0, wtimeout: 0, fsync: false, j:false);
  +  static const UNACKNOWLEDGED =
  +      const WriteConcern(w: 0, wtimeout: 0, fsync: false, j: false);
   
     /**
      * Write operations that use this write concern will wait for acknowledgement from the primary server before returning.
      * Exceptions are raised for network issues, and server errors.
      */
  -  static const ACKNOWLEDGED = const WriteConcern(w: 1, wtimeout: 0, fsync: false, j:false);
  +  static const ACKNOWLEDGED =
  +      const WriteConcern(w: 1, wtimeout: 0, fsync: false, j: false);
   
     /**
      * Exceptions are raised for network issues, and server errors; waits for at least 2 servers for the write operation.
      */
  -  static const REPLICA_ACKNOWLEDGED= const WriteConcern(w: 2, wtimeout: 0, fsync: false, j:false);
  +  static const REPLICA_ACKNOWLEDGED =
  +      const WriteConcern(w: 2, wtimeout: 0, fsync: false, j: false);
   
     /**
      * Exceptions are raised for network issues, and server errors; the write operation waits for the server to flush
      * the data to disk.
      */
  -  static const FSYNCED = const WriteConcern(w: 1, wtimeout: 0, fsync: true, j: false);
  +  static const FSYNCED =
  +      const WriteConcern(w: 1, wtimeout: 0, fsync: true, j: false);
   
     /**
      * Exceptions are raised for network issues, and server errors; the write operation waits for the server to
      * group commit to the journal file on disk.
      */
  -  static const JOURNALED = const WriteConcern(w: 1, wtimeout: 0, fsync: false, j: true);
  +  static const JOURNALED =
  +      const WriteConcern(w: 1, wtimeout: 0, fsync: false, j: true);
   
     /**
      * Exceptions are raised for network issues, and server errors; waits on a majority of servers for the write operation.
      */
  -  static const MAJORITY = const WriteConcern(w: "majority", wtimeout: 0, fsync: false, j: false);
  +  static const MAJORITY =
  +      const WriteConcern(w: "majority", wtimeout: 0, fsync: false, j: false);
   
     /**
      * Gets the getlasterror command for this write concern.
  
positive.code:   }
  
    Future close() {
      _log.fine(()=>'$this closed');
      state = State.CLOSED;
      var _cm = _connectionManager;
      _connectionManager = null;
  
negative.code: 
    Stream<Map> _listCollectionsCursor([Map filter = const {}]) {
      if (this._masterConnection.serverCapabilities.listCollections) {
        return new ListCollectionsCursor(this, filter).stream;
      } else {
        // Using system collections (pre v3.0 API)
        Map selector = {};
        // If we are limiting the access to a specific collection name
        if (filter.containsKey('name')) {
          selector["name"] = "${this.databaseName}.${filter['name']}";
        }
        return new Cursor(
            this,
            new DbCollection(this, DbCommand.SYSTEM_NAMESPACE_COLLECTION),
            selector).stream;
      }
    }
  
    /// This method uses system collections and therefore do not work on MongoDB v3.0 with and upward
    /// with WiredTiger
    /// Use `getCollectionInfos` instead
  