David Cantú

> On Windows, this API would generate a new random directory name (possibly using Guid.NewGuid) I guess you can use [Path.GetRandomFileName()](https://docs.microsoft.com/en-us/dotnet/api/system.io.path.getrandomfilename?view=net-6.0) rather than a GUID.

> Does it prevent roundtripping / another tool deserializing tar archives produced by TarWriter? I tried opening with 7Zip an archive created with TarFile.CreateFromDirectory and that worked just fine. >...

> What is the risk of breaking something else if we fix this? This might be as easy as replacing `Encoding.ASCII` for `Encoding.UTF8` and nothig else.

> they'll produce garbage names in the file system? Right, even our own `TarReader` will read them back as garbled as I show in the snippet in the original post.

@danmoseley I wasn't planning on adding interop tests to `System.Formats.Tar.Tests`. I did play a bit with GNU Tar with all the formats we support, to see how they handled non-ascii...

Last commit addresses the problem with ustar prefix (https://github.com/dotnet/runtime/issues/75360) and partially addresses the truncation issue (https://github.com/dotnet/runtime/issues/75921) as the name won't be truncated on formats that do not suppoort unlimited size...

Updated PR to also fix the other two related issues, field truncation and ustar prefix logic (see description).

Closing in favor of https://github.com/dotnet/runtime/pull/76404

@mairaw

@jakobbotsch the times that the process hangs `OnSigChild` is not being called, `SetExited()` is also not called somewhere else (that is called on OnSigChild->CheckChildren->TryReapChild->SetExited). This means that `_exitedEvent` is never...