proc establishConnection(sock: AsyncSocket; username: string;
                         password: string = ""; database: string = "";
    connectAttrs: Table[string, string] = default(Table[string, string])): Future[
    Connection] {...}{.raises: [Exception, ValueError],
                  tags: [ReadIOEffect, RootEffect, TimeEffect, IOEffect].}

proc open(uriStr: string | uri.Uri): Future[Connection]

proc open(connection, user, password: string; database = "";
          connectAttrs: Table[string, string] = default(Table[string, string])): Future[
    Connection] {...}{.raises: [Exception, ValueError],
                  tags: [RootEffect, ReadIOEffect, TimeEffect, IOEffect].}

proc close(conn: Connection): Future[void] {...}{.raises: [Exception],
    tags: [TimeEffect, RootEffect, ReadIOEffect].}