panic: tried to serialize Uninitialized

We got a panic from one of our linux users when opening a sled database (that it has created), haven't seen this before and only gotten it twice ever (both times today). opening up this issue as there didn't seem to have been any other reports of this specific panic.

could potentially be some local corruption on that specific machine also, if that was the case would it be possible to fail opening the db on this instead of panicking? though understand if it could be hard to handle everything to errors rather than panics.

Context:

sled version: 0.34.7
rustc version: 1.56.1
operating system: Linux 5.8.0-48-generic (Ubuntu)

logs, panic messages, stack traces:

tried to serialize Uninitialized, file: /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/sled-0.34.7/src/serialization.rs:662:18, thread: main

6   std::panicking::rust_panic_with_hook (panicking.rs:628)
7   std::panicking::begin_panic_handler::{{closure}} (panicking.rs:521)
8   std::sys_common::backtrace::__rust_end_short_backtrace (backtrace.rs:141)
9   rust_begin_unwind (panicking.rs:517)
10  std::panicking::begin_panic_fmt (panicking.rs:460)
11  sled::pagecache::snapshot::PageState::serialized_size (serialization.rs:662)
12  [inlined] sled::pagecache::snapshot::Snapshot::serialized_size::{{closure}} (serialization.rs:507)
13  [inlined] core::iter::adapters::map::map_fold::{{closure}} (map.rs:84)
14  [inlined] core::iter::traits::iterator::Iterator::fold (iterator.rs:2170)
15  [inlined] core::iter::adapters::map::Map<T>::fold (map.rs:124)
16  [inlined] u64::sum (accum.rs:42)
17  [inlined] core::iter::traits::iterator::Iterator::sum (iterator.rs:2985)
18  [inlined] sled::pagecache::snapshot::Snapshot::serialized_size (serialization.rs:504)
19  [inlined] sled::serialization::Serialize::serialize (serialization.rs:35)
20  [inlined] sled::pagecache::snapshot::write_snapshot (snapshot.rs:515)
21  [inlined] sled::pagecache::snapshot::advance_snapshot (snapshot.rs:365)
22  sled::pagecache::snapshot::read_snapshot_or_default (snapshot.rs:450)
23  sled::pagecache::PageCache::start (mod.rs:588)
24  [inlined] sled::context::Context::start (context.rs:44)
25  sled::db::Db::start_inner (db.rs:70)
26  sled::config::Config::open (config.rs:354)

If snapshot apply() calls,

sled/src/pagecache/snapshot.rs

Line 287 in c840fe7