Unknown bytes written to client trace file in CopyingExternalClient event

[jessestimpson]

Using foundationdb-clients version v7.3.31 and using external_client_library with client_threads_per_version > 1, I'm seeing unknown bytes written to a client trace log. The trace event is CopyingExternalClient and the field is TempPath. I confirmed on both a macOS system and an Ubuntu system.

Here's an example trace. The json format has the same issue.

<Event Severity="10"
Time="1743790582.848125"
DateTime="2025-04-04T18:16:22Z"
Type="CopyingExternalClient"
ID="0000000000000000"
FileName="libfdb_c.dylib"
LibraryPath="/usr/local/lib/libfdb_c.dylib"
TempPath="/tmp/libfdb_c.dylib-hU5Jsp\x00\x00pf\xffk\x01\x00\x00\x00\x94\xde\xb3@\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x85g\x01\x00`\x00\x00p\x00\x06\x0b\x01\x00\x00\x00p\x00\x06\x0b\x01\x00\x00\x00\x00\x00\x06\x0b\x01\x00\x00\x00\xd0g\xffk\x01\x00\x00\x00\x90\xc7\x9b@\x01\x00\x00\x00\xb0f\xffk\x01\x00\x00\x00\x1c\xf9\xb7@\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xb0\x88c\x92\x01\x00\x00\x00\x08\x0e\x1cA\x01\x00\x00\x00H\x8a\x1cA\x01\x00\x00\x00\xa..."
ThreadID="13800183810239497250"
Machine="127.0.0.1:12917"
LogGroup="default"
ClientDescription="primary-7.3.31-17449682910749848374" />

Note: I manually entered newlines into the block above so that it rendered without horizontal scrolling in GitHub.