backend: refactor backend Connections and HasAtomicReplace into Properties

internal/backend/b2/b2.go

@@ -154,8 +154,11 @@ func (be *b2Backend) SetListMaxItems(i int) {
 	be.listMaxItems = i
 }
 
-func (be *b2Backend) Connections() uint {
-	return be.cfg.Connections
+func (be *b2Backend) Properties() backend.Properties {
+	return backend.Properties{
+		Connections:      be.cfg.Connections,
+		HasAtomicReplace: true,
+	}
 }
 
 // Hasher may return a hash function for calculating a content hash for the backend
@@ -163,11 +166,6 @@ func (be *b2Backend) Hasher() hash.Hash {
 	return nil
 }
 
-// HasAtomicReplace returns whether Save() can atomically replace files
-func (be *b2Backend) HasAtomicReplace() bool {
-	return true
-}
-
 // IsNotExist returns true if the error is caused by a non-existing file.
 func (be *b2Backend) IsNotExist(err error) bool {
 	// blazer/b2 does not export its error types and values,