[#373] blobovniczatree: Add metrics

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/blobstor/blobovniczatree/option.go

@@ -21,6 +21,7 @@ type cfg struct {
 	blzOpts         []blobovnicza.Option
 	// reportError is the function called when encountering disk errors.
 	reportError func(string, error)
+	metrics     Metrics
 }
 
 type Option func(*cfg)
@@ -40,6 +41,7 @@ func initConfig(c *cfg) {
 		blzShallowDepth: defaultBlzShallowDepth,
 		blzShallowWidth: defaultBlzShallowWidth,
 		reportError:     func(string, error) {},
+		metrics:         &noopMetrics{},
 	}
 }
 
@@ -91,3 +93,9 @@ func WithObjectSizeLimit(sz uint64) Option {
 		c.blzOpts = append(c.blzOpts, blobovnicza.WithObjectSizeLimit(sz))
 	}
 }
+
+func WithMetrics(m Metrics) Option {
+	return func(c *cfg) {
+		c.metrics = m
+	}
+}