Tweak: Remove redundant UnwindDetector from AutoCloseFd.

This is redundant as the destructor already uses a recoverable assertion, which will not throw during unwind.

I have long assumed AutoCloseFd wrapped only an integer and was shocked to realize it was more that that...

c++/src/kj/io.c++

@@ -326,14 +326,13 @@ void VectorOutputStream::grow(size_t minSize) {
 
 AutoCloseFd::~AutoCloseFd() noexcept(false) {
   if (fd >= 0) {
-    unwindDetector.catchExceptionsIfUnwinding([&]() {
-      // Don't use SYSCALL() here because close() should not be repeated on EINTR.
-      if (miniposix::close(fd) < 0) {
-        KJ_FAIL_SYSCALL("close", errno, fd) {
-          break;
-        }
+    // Don't use SYSCALL() here because close() should not be repeated on EINTR.
+    if (miniposix::close(fd) < 0) {
+      KJ_FAIL_SYSCALL("close", errno, fd) {
+        // This ensures we don't throw an exception if unwinding.
+        break;
       }
-    });
+    }
   }
 }
 

c++/src/kj/io.h

@@ -300,7 +300,6 @@ public:
 
 private:
   int fd;
-  UnwindDetector unwindDetector;
 };
 
 inline auto KJ_STRINGIFY(const AutoCloseFd& fd)