Disable idle checks for cluster connection

cluster.go

@@ -627,6 +627,8 @@ func (opt *ClusterOptions) init() {
 }
 
 func (opt *ClusterOptions) clientOptions() *Options {
+	const disableIdleCheck = -1
+
 	return &Options{
 		Password: opt.Password,
 		ReadOnly: opt.ReadOnly,
@@ -640,5 +642,6 @@ func (opt *ClusterOptions) clientOptions() *Options {
 		IdleTimeout: opt.IdleTimeout,
 
 		// IdleCheckFrequency is not copied to disable reaper
+		IdleCheckFrequency: disableIdleCheck,
 	}
 }

options.go

@@ -53,6 +53,7 @@ type Options struct {
 	IdleTimeout time.Duration
 	// Frequency of idle checks.
 	// Default is 1 minute.
+	// When minus value is set, then idle check is disabled.
 	IdleCheckFrequency time.Duration
 
 	// Enables read only queries on slave nodes.