pool: Add noop statistic

Signed-off-by: Evgenii Baidakov <evgenii@nspcc.io>

pool/pool.go

@@ -1595,9 +1595,9 @@ func fillDefaultInitParams(params *InitParameters, cache *sessionCache) {
 				return nil
 			})
 
-			var statistic ClientStatus
-			if params.statistic == nil {
-				// statistic is disabled by default.
+			// statistic is disabled by default.
+			var statistic = params.statistic
+			if statistic == nil {
 				statistic = newNoOpClientStatusMonitor(prm.address)
 			}
 

pool/status.go

@@ -0,0 +1,46 @@
+package pool
+
+import (
+	"time"
+)
+
+// noOpClientStatusMonitor is using by default for pool.
+type noOpClientStatusMonitor struct {
+	addr string
+}
+
+func newNoOpClientStatusMonitor(addr string) noOpClientStatusMonitor {
+	return noOpClientStatusMonitor{addr: addr}
+}
+
+func (n noOpClientStatusMonitor) updateErrorRate(_ error) {
+}
+
+func (n noOpClientStatusMonitor) incRequests(_ time.Duration, _ MethodIndex) {
+}
+
+func (n noOpClientStatusMonitor) isHealthy() bool {
+	return true
+}
+
+func (n noOpClientStatusMonitor) setUnhealthy() {
+}
+
+func (n noOpClientStatusMonitor) setHealthy() {
+}
+
+func (n noOpClientStatusMonitor) address() string {
+	return n.addr
+}
+
+func (n noOpClientStatusMonitor) currentErrorRate() uint32 {
+	return 0
+}
+
+func (n noOpClientStatusMonitor) overallErrorRate() uint64 {
+	return 0
+}
+
+func (n noOpClientStatusMonitor) methodsStatus() []statusSnapshot {
+	return nil
+}