public static bool IsNot(this SyncPrimitiveCapabilityUC src, SyncPrimitiveCapabilityUC flags)
 => !Is(src, flags);
 public static bool Is(this SyncPrimitiveCapabilityUC src, SyncPrimitiveCapabilityUC flags)
 => flags == 0 ? src == 0  : (src & flags) == flags;