[ios, osx] Allow creating invalid offline packs

Removed NS_UNAVAILABLE attribute from -[MGLOfflinePack init]. Packs initialized with this initializer are doomed to invalidity.

Fixes #4421.

1 files changed, 4 insertions, 2 deletions

diff --git a/platform/darwin/include/MGLOfflinePack.h b/platform/darwin/include/MGLOfflinePack.h
index 666e442d26..185bba038c 100644
--- a/platform/darwin/include/MGLOfflinePack.h
+++ b/platform/darwin/include/MGLOfflinePack.h
@@ -83,6 +83,10 @@ typedef struct MGLOfflinePackProgress {
 /**
  An `MGLOfflinePack` represents a collection of resources necessary for viewing
  a region offline to a local database.
+ 
+ To create an instance of `MGLOfflinePack`, use the
+ `+[MGLOfflineStorage addPackForRegion:withContext:completionHandler:]` method.
+ A pack created using `-[MGLOfflinePack init]` is immediately invalid.
  */
 @interface MGLOfflinePack : NSObject
 
@@ -123,8 +127,6 @@ typedef struct MGLOfflinePackProgress {
  */
 @property (nonatomic, readonly) MGLOfflinePackProgress progress;
 
-- (instancetype)init NS_UNAVAILABLE;
-
 /**
  Resumes downloading if the pack is inactive.