App 子线程中初始化 APNGImage 偶现 crash

线上崩溃日志收集如下：

#32 Thread SIGABRT

0 ??? 0x00000001acdf0f9c + 0
1 ??? 0x00000001e9ff75c0 + 0
2 ??? 0x00000001f2930000 + 0
3 ??? 0x00000001acdf1484 + 0
4 ??? 0x00000001acdff928 + 0
5 libdyld.dylib dyld_stub_binder + 60
6 APPName read (Reader.swift:104)
7 APPName read (<compiler-generated>:0)
8 APPName init (APNGDecoder.swift:78)
9 APPName init (APNGDecoder.swift:67)
10 APPName loadEmoticonMapper (<compiler-generated>:0)
11 APPName _$sIeg_IeyB_TR (<compiler-generated>:0)
12 libdispatch.dylib __dispatch_call_block_and_release + 24

crash 统计中，目前的用户设备系统版本均为 iOS13+。

• loadEmoticonMapper 中加载 APNGImage 的代码在子线程调用，通过如下方式使用
  if let image = try? APNGImage(fileURL: url, scale: 3) { /// }

为何 try catch 无法避免 APNGDecoder.init() 方法引起的 crash 呢？

Start with loadEmoticonMapper and follow APNGImage initialization into APNGDecoder.swift:67 and :78, then inspect the read call at Reader.swift:104. Determine the failure path represented by the SIGABRT and explain why the shown try? usage does not prevent it; done means a confirmed cause and a documented or reproducible resolution.