Panics when server is left running after a few sessions

[thatdevsherry]

Panics appear after running a few local sessions and responder was left running. Might be related to REFWAIT given the time they appeared after.

.....
2025-11-14T13:55:08.020289Z  INFO twamp_rs::server: Read Stop-Sessions

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(19), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(33), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(47), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(61), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(75), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(89), ...)

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:101:47:
called `Result::unwrap()` on an `Err` value: ()

thread 'tokio-runtime-worker' (35610) panicked at examples/responder/responder.rs:105:60:
called `Result::unwrap()` on an `Err` value: JoinError::Panic(Id(103), ...)