Bug 2318288

.`header_read` times are now reported accurately Previously, the `header_read` time was calculated based on the throttle timestamp (`throttle_stamp`), instead of the receive timestamp (`recv_stamp`). Due to mismatched timestamps, a logical error occurred and as a result, incorrect `header_read` times were reported. This led to inaccurate performance metrics, and triggered false alarms in monitoring systems. The inaccuracies also masked actual performance issues in cases that the reported `header_read` times were artificially inflated by throttling delays. With this fix, the code is modified to use the receive timestamp (`recv_stamp`) as the basis for calculating the `header_read` time, regardless of a throttling event. The `header_read` time now represents the time the header was received and not the time the corresponding operation was delayed. As a result, accurate `header_read` times are reported, reflecting the actual time the header was received. This fix provides more reliable performance metrics, improves the accuracy of monitoring systems, and helps enhance analysis and optimization of system performance.