[tracing] tracepoint for utxocache flushes

Signed-off-by: Arnab Sen <arnabsen1729@gmail.com>

src/validation.cpp

@@ -2101,6 +2101,14 @@ bool CChainState::FlushStateToDisk(
             nLastFlush = nNow;
             full_flush_completed = true;
         }
+        TRACE6(utxocache, flush,
+            (int64_t)(GetTimeMicros() - nNow.count()), // in microseconds (µs)
+            (u_int32_t)mode,
+            (u_int64_t)coins_count,
+            (u_int64_t)coins_mem_usage,
+            (bool)fFlushForPrune,
+            (bool)fDoFullFlush
+        );
     }
     if (full_flush_completed) {
         // Update best block in wallet (so we can detect restored wallets).