PoolBox: Counter != 1 on drop 0

[JakkuSakura]

I'm on different threads, passing ArenaBox<FixBuffer> created by Arena. Not sure why whould this happen. It happens sometimes

#[repr(C)]
pub struct FixedBuffer {
    len: usize,
    content: [u8; 256],
}
impl FixedBuffer {
    pub fn new() -> FixedBuffer {
        unsafe {
            FixedBuffer {
                content: MaybeUninit::uninit().assume_init(),
                len: 0,
            }
        }
    }
}
impl Default for FixedBuffer {
    fn default() -> Self {
        FixedBuffer::new()
    }
}

panic: thread 'unnamed' panicked at 'PoolBox: Counter != 1 on drop 0': /home/ubuntu/.cargo/registry/src/github.com-1ecc6299db9ec823/shared_arena-0.8.4/src/arena_box.rs:151
   0: log_panics::init::{{closure}}
   1: std::panicking::rust_panic_with_hook
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/panicking.rs:626:17
   2: std::panicking::begin_panic_handler::{{closure}}
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/panicking.rs:519:13
   3: std::sys_common::backtrace::__rust_end_short_backtrace
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/sys_common/backtrace.rs:141:18
   4: rust_begin_unwind
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/panicking.rs:515:5
   5: std::panicking::begin_panic_fmt
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/panicking.rs:457:5
   6: <shared_arena::arena_box::ArenaBox<T> as core::ops::drop::Drop>::drop
   7: <public_api::api_controller::imp::PublicApiControllerWorkImpl<Api,Buffer0> as public_api::api_controller::PublicApiControllerWork>::process_work
   8: std::sys_common::backtrace::__rust_begin_short_backtrace
   9: core::ops::function::FnOnce::call_once{{vtable.shim}}
  10: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/alloc/src/boxed.rs:1575:9
      <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/alloc/src/boxed.rs:1575:9
      std::sys::unix::thread::Thread::new::thread_start
             at /rustc/c1e8f3a5857c3c8d095fd212acc6ed442f4cc58b/library/std/src/sys/unix/thread.rs:71:17
  11: start_thread
  12: <unknown>
    

[JakkuSakura]

It turns out my RingBuffer is unsafe when overflowing. It caused this problem.