add handshake failure stage accounting

src/stats/core_getters.rs

@@ -38,6 +38,21 @@ impl Stats {
         out
     }
 
+    pub fn get_handshake_failure_stage_counts(&self) -> Vec<(String, u64)> {
+        let mut out: Vec<(String, u64)> = self
+            .handshake_failure_stages
+            .iter()
+            .map(|entry| {
+                (
+                    entry.key().to_string(),
+                    entry.value().load(Ordering::Relaxed),
+                )
+            })
+            .collect();
+        out.sort_by(|a, b| a.0.cmp(&b.0));
+        out
+    }
+
     pub fn get_accept_permit_timeout_total(&self) -> u64 {
         self.accept_permit_timeout_total.load(Ordering::Relaxed)
     }