DownloadSession接口怎么定义

DownloadSession接口定义

public class DownloadSession {
    DownloadSession(Configuration conf, String projectName, String tableName,
                    String partitionSpec) throws TunnelException
    DownloadSession(Configuration conf, String projectName, String tableName,
                    String partitionSpec, String downloadId) throws TunnelException
    public String getId()
    public long getRecordCount()
    public TableSchema getSchema()
    public TableTunnel.DownloadStatus getStatus()
    public RecordReader openRecordReader(long start, long count)
    public RecordReader openRecordReader(long start, long count, boolean compress)
}