This Integer32 reports the current transport window size, expressed as the number of buffers currently outstanding (unacknowledged) on the connection. A shrinking window size signals that the receiving side is applying flow control or that acknowledgments are lagging, both of which cap achievable throughput. For example, an admin troubleshooting slow transfers might watch cnt2TransportWindowSize stay pinned near zero, indicating the connection is starved waiting on acks before it can send more.