sync example panicing with "already subscribed"

[b5]

@divagant-martian & I have both replicated this. I was running main branch, commit 4ef3611

Error:

thread 'main' panicked at 'already subscribed', iroh/examples/sync.rs:277:38

to replicate run:

cargo run --example sync --features="example-sync" -- open x

Full output:

$ export RUST_BACKTRACE=1
b5 at number-0 in ~/code/iroh (main)
$ cargo run --example sync --features="example-sync" -- open foo
    Finished dev [unoptimized + debuginfo] target(s) in 0.20s
     Running `target/debug/examples/sync open foo`
> our secret key: j37vi7ntiitnhnrqqqt5mpd7o3vjti44yqywxhdo6gc4zd4o67ba
> using DERP servers: https://derp.iroh.network./, https://eu1.derp.iroh.network./
> our peer id: yrquuqsvrn5atzkcdwby43hiiomz3nuby7n4472hu3im3qpkfwia
> opening document foo as namespace atqlw…uq and waiting for peers to join us...
> ticket to join us: atqlwoptbmnd724j6u3mso7bkbkuqlpxjbtuwagsnznhk53xaluqcigemffeevmlpie6kqq5qohgz2cdtgo3naoh3phh6r5g2dg4d2rnsadqasczeaq33dadadakqrbzxwgagagavbcevpmmamasmacaifjxj2aaaaaaaaaaaaianuwbamasmacaifjxj2aaaaaaaaaaaaibfuwbamasmacaifjxj2aaaaaaaaaaaaibhuwbamasmacaifjxj2aaaaaaaaaaaaibluwbamaqc
> storage directory: "/var/folders/3z/8gpmzsnd5sd7stqq9z5n0v040000gn/T/iroh-sync-yrquuqsvrn5atzkcdwby43hiiomz3nuby7n4472hu3im3qpkfwia"
> opening doc yne55…cq
> ready to accept commands
> type `help` for a list of commands
thread 'main' panicked at 'already subscribed', iroh/examples/sync.rs:274:38
stack backtrace:
>>    0: rust_begin_unwind
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/std/src/panicking.rs:593:5
   1: core::panicking::panic_fmt
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/panicking.rs:67:14
   2: core::panicking::panic_display
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/panicking.rs:150:5
   3: core::panicking::panic_str
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/panicking.rs:134:5
   4: core::option::expect_failed
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/option.rs:1952:5
   5: core::option::Option<T>::expect
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/option.rs:898:21
   6: sync::run::{{closure}}
             at ./iroh/examples/sync.rs:274:22
   7: sync::main::{{closure}}
             at ./iroh/examples/sync.rs:94:15
   8: tokio::runtime::park::CachedParkThread::block_on::{{closure}}
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/park.rs:282:63
   9: tokio::runtime::coop::with_budget
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/coop.rs:107:5
  10: tokio::runtime::coop::budget
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/coop.rs:73:5
  11: tokio::runtime::park::CachedParkThread::block_on
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/park.rs:282:31
  12: tokio::runtime::context::blocking::BlockingRegionGuard::block_on
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/context/blocking.rs:66:9
  13: tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/scheduler/multi_thread/mod.rs:87:13
  14: tokio::runtime::context::runtime::enter_runtime
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/context/runtime.rs:65:16
  15: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/scheduler/multi_thread/mod.rs:86:9
  16: tokio::runtime::runtime::Runtime::block_on
             at /Users/b5/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.32.0/src/runtime/runtime.rs:349:45
  17: sync::main
             at ./iroh/examples/sync.rs:94:5
  18: core::ops::function::FnOnce::call_once
             at /rustc/5680fa18feaa87f3ff04063800aec256c3d4b4be/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.