1 files changed, 15 insertions, 1 deletions
diff --git a/src/swarm/stats.rs b/src/swarm/stats.rs
index 74076a4..de63962 100644
--- a/src/swarm/stats.rs
+++ b/src/swarm/stats.rs
@@ -59,7 +59,7 @@ pub(crate) struct Propagation {
 }
 
 impl Propagation {
-    fn record(&mut self, delay_ms: i64) {
+    pub(crate) fn record(&mut self, delay_ms: i64) {
         if delay_ms < 0 {
             self.ahead += 1;
         }
@@ -73,6 +73,20 @@ impl Propagation {
         self.sum_ms += delay_ms;
     }
 
+    /// The bound of the bucket by which `quantile` of the delays came: None if beyond
+    /// the last bound, or none came.
+    pub(crate) fn within(&self, quantile: f64) -> Option<u64> {
+        let wanted = (self.count as f64 * quantile).ceil() as u64;
+        let mut seen = 0;
+        for (bound, count) in self.buckets() {
+            seen += count;
+            if seen >= wanted && seen > 0 {
+                return bound;
+            }
+        }
+        None
+    }
+
     /// Each bucket's upper bound (None for the last) and count.
     pub(crate) fn buckets(&self) -> impl Iterator<Item = (Option<u64>, u64)> + '_ {
         PROPAGATION_BUCKETS_MS