Add Syncer interface.

Author: pwood

impl/file/file.go

@@ -36,6 +36,7 @@ type file struct {
 }
 
 var _ persistence.Section = (*file)(nil)
+var _ persistence.Syncer = (*file)(nil)
 
 func (f *file) Section(key ...string) persistence.Section {
 	f.m.Lock()

interface.go

@@ -22,6 +22,10 @@ type Section interface {
 	Delete(key string) bool
 }
 
+type Syncer interface {
+	Sync()
+}
+
 type ValueType uint8
 
 const (