failed to run null example code

[gaowayne]

please check below error screen, it panic

ayne@wayne-virtual-machine:~/wayne/rust/fuse-rs$ RUST_BACKTRACE=full cargo run --example null
warning: field `data` is never read
  --> src/request.rs:39:5
   |
35 | pub struct Request<'a> {
   |            ------- field in this struct
...
39 |     data: &'a [u8],
   |     ^^^^
   |
   = note: `#[warn(dead_code)]` on by default
   = note: `Request` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis

warning: `fuse` (lib) generated 1 warning
    Finished dev [unoptimized + debuginfo] target(s) in 0.13s
     Running `target/debug/examples/null`
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', examples/null.rs:10:44
stack backtrace:
   0:     0x56325ee3fa13 - std::backtrace_rs::backtrace::libunwind::trace::he0156af2558114c2
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x56325ee3fa13 - std::backtrace_rs::backtrace::trace_unsynchronized::h1e2672bcf5105eb5
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x56325ee3fa13 - std::sys_common::backtrace::_print_fmt::haa919a14d8d859ec
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x56325ee3fa13 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hf15e8f9e6884dd5f
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x56325ee57fcc - core::fmt::write::he42254d9e3c27115
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/fmt/mod.rs:1202:17
   5:     0x56325ee2c135 - std::io::Write::write_fmt::hfb37e0ab3a125c66
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/io/mod.rs:1679:15
   6:     0x56325ee2e314 - std::sys_common::backtrace::_print::h8078bdb0e2e92b53
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x56325ee2e314 - std::sys_common::backtrace::print::h09fd65486fb9c4f7
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x56325ee2e314 - std::panicking::default_hook::{{closure}}::hb89b98c578903f40
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:295:22
   9:     0x56325ee2df54 - std::panicking::default_hook::h27aa44be03b01ac8
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:314:9
  10:     0x56325ee2e8f3 - std::panicking::rust_panic_with_hook::he7013d2ea706cde0
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:698:17
  11:     0x56325ee3ffa9 - std::panicking::begin_panic_handler::{{closure}}::hd66fe345adc7bed2
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:586:13
  12:     0x56325ee3fb54 - std::sys_common::backtrace::__rust_end_short_backtrace::ha2b47ffe9f27aed9
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:138:18
  13:     0x56325ee2e5e2 - rust_begin_unwind
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:584:5
  14:     0x56325ec56783 - core::panicking::panic_fmt::hbfca70bd08ba6212
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/panicking.rs:142:14
  15:     0x56325ec5664d - core::panicking::panic::hc1bbfa9fa05e63d3
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/panicking.rs:48:5
  16:     0x56325ec5bbf6 - core::option::Option<T>::unwrap::h4d9b1aca8f9efd24
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/option.rs:775:21
  17:     0x56325ec5b9fe - null::main::h242d5a3c8f60c5b2
                               at /home/wayne/wayne/rust/fuse-rs/examples/null.rs:10:22
  18:     0x56325ec5d75b - core::ops::function::FnOnce::call_once::h1a81777304d08d20
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/ops/function.rs:248:5
  19:     0x56325ec5e63e - std::sys_common::backtrace::__rust_begin_short_backtrace::h9d94d6bc6c4b929c
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/sys_common/backtrace.rs:122:18
  20:     0x56325ec5e6b1 - std::rt::lang_start::{{closure}}::h88427632f265d356
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/rt.rs:166:18
  21:     0x56325ee2b678 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h62af992155415807
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/core/src/ops/function.rs:283:13
  22:     0x56325ee2b678 - std::panicking::try::do_call::hcfafbbba7d4f6a6c
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:492:40
  23:     0x56325ee2b678 - std::panicking::try::h7ee1bfcad42abe9b
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:456:19
  24:     0x56325ee2b678 - std::panic::catch_unwind::h009aa132eb8dd7d2
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panic.rs:137:14
  25:     0x56325ee2b678 - std::rt::lang_start_internal::{{closure}}::h93ae259af980c7d0
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/rt.rs:148:48
  26:     0x56325ee2b678 - std::panicking::try::do_call::ha0627c997265a210
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:492:40
  27:     0x56325ee2b678 - std::panicking::try::h64a0afc1377cc785
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panicking.rs:456:19
  28:     0x56325ee2b678 - std::panic::catch_unwind::h1c61ea510b397b89
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/panic.rs:137:14
  29:     0x56325ee2b678 - std::rt::lang_start_internal::ha75927e1903320fe
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/rt.rs:148:20
  30:     0x56325ec5e68a - std::rt::lang_start::hf110f00bd0d8cd3a
                               at /build/rustc-Oic09u/rustc-1.65.0+dfsg0ubuntu1/library/std/src/rt.rs:165:17
  31:     0x56325ec5bae1 - main
  32:     0x7f9884e29d90 - __libc_start_call_main
                               at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  33:     0x7f9884e29e40 - __libc_start_main_impl
                               at ./csu/../csu/libc-start.c:392:3
  34:     0x56325ec56965 - _start
  35:                0x0 - <unknown>
wayne@wayne-virtual-machine:~/wayne/rust/fuse-rs$