   mutating func requestUniqueMutableBackingBuffer(minimumCapacity: Int)
     -> NativeBuffer?
   {
-    if _fastPath(isUniquelyReferenced() && _isNative) {
+    if _fastPath(isUniquelyReferenced()) {
       let b = _native
       if _fastPath(b.capacity >= minimumCapacity) {
         return b

    if !_isClassOrObjCExistential(T.self) {
      return _storage.isUniquelyReferencedOrPinned_native_noSpareBits()
    }
    return _storage.isUniquelyReferencedOrPinnedNative()
  }

  /// Convert to an NSArray.

    if !_isClassOrObjCExistential(T.self) {
      return _storage.isUniquelyReferenced_native_noSpareBits()
    }
    return _storage.isUniquelyReferencedNative() && _isNative
  }

  /// Return true iff this buffer's storage is either
