Reword the new comment in include/h2o.h
@@ -993,10 +993,10 @@ typedef struct st_h2o_conn_callbacks_t {
*/
quicly_tracer_t *(*get_tracer)(h2o_conn_t *conn);
/**
- * An optional callback reporting an estimate of the connection round-trip
- * time in microseconds obtained by timing the acknowledgement of our
- * settings frame in HTTP/2. Only supported for H2. The callback will
- * return a negative value if the information is not yet available.
+ * An optional callback reporting an RTT estimate between the HTTP server and the HTTP client, measured in microseconds. At the
+ * moment, this callback is available only for HTTP/2. For HTTP/2, time difference between when the SETTINGS frame was sent and
+ * when a SETTINGS-ack was received is used as the estimate. The callback will return a negative value if the information is not
+ * yet available.
*/
int64_t (*get_rtt_estimate)(h2o_conn_t *conn);
/**
