I/O Time (Threads View)
These segments in the timeline are associated with blocking times that are categorized as I/O. This means that a thread is waiting for an I/O operation to finish. The thread may have been blocked in an API, or by an I/O-related kernel wait that the Concurrency Visualizer is counting as I/O. APIs such as CreateFile(), ReadFile(), and WSARecv() fall into this group.