[#1302] writecache: Allow to specify custom page size

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

pkg/local_object_storage/writecache/options.go

@@ -48,6 +48,8 @@ type options struct {
 	metrics Metrics
 	// disableBackgroundFlush is for testing purposes only.
 	disableBackgroundFlush bool
+	// pageSize is bbolt's page size config value
+	pageSize int
 }
 
 // WithLogger sets logger.
@@ -173,3 +175,10 @@ func WithDisableBackgroundFlush() Option {
 		o.disableBackgroundFlush = true
 	}
 }
+
+// WithPageSize sets bbolt's page size.
+func WithPageSize(s int) Option {
+	return func(o *options) {
+		o.pageSize = s
+	}
+}