rust: add example code and mention in the readme

[axic]

This is what the documentation looks like:

[codecov]

Codecov Report

Merging #724 (27a33f4) into master (459dfb9) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #724   +/-   ##
=======================================
  Coverage   99.34%   99.34%           
=======================================
  Files          73       73           
  Lines       11125    11125           
=======================================
  Hits        11052    11052           
  Misses         73       73           

Flag	Coverage Δ
rust	99.78% <ø> (ø)
spectests	90.84% <ø> (ø)
unittests	99.32% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
bindings/rust/src/lib.rs	99.78% <ø> (ø)

[axic]

Not sure why there is a double free, fizzy_free_instance seems to be called once, and fizzy_free_module is not called.

* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
  * frame #0: 0x00007fff6e8ff33a libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fff6e9bbe60 libsystem_pthread.dylib`pthread_kill + 430
    frame #2: 0x00007fff6e886808 libsystem_c.dylib`abort + 120
    frame #3: 0x00007fff6e97c50b libsystem_malloc.dylib`malloc_vreport + 548
    frame #4: 0x00007fff6e97f40f libsystem_malloc.dylib`malloc_report + 151
    frame #5: 0x000000010000a7c5 fizzy-integration-test`std::__1::_DeallocateCaller::__do_call(__ptr=0x0000000100405870) at new:320:12
    frame #6: 0x000000010000a779 fizzy-integration-test`std::__1::_DeallocateCaller::__do_deallocate_handle_size(__ptr=0x0000000100405870, __size=2) at new:278:12
    frame #7: 0x000000010000a705 fizzy-integration-test`std::__1::_DeallocateCaller::__do_deallocate_handle_size_align(__ptr=0x0000000100405870, __size=2, __align=1) at new:254:14
    frame #8: 0x000000010000a6a5 fizzy-integration-test`std::__1::__libcpp_deallocate(__ptr=0x0000000100405870, __size=2, __align=1) at new:326:3
    frame #9: 0x000000010000b986 fizzy-integration-test`std::__1::allocator<fizzy::ValType>::deallocate(this=0x00000001004053c0, __p=0x0000000100405870, __n=2) at memory:1817:10
    frame #10: 0x000000010000b845 fizzy-integration-test`std::__1::allocator_traits<std::__1::allocator<fizzy::ValType> >::deallocate(__a=0x00000001004053c0, __p=0x0000000100405870, __n=2) at memory:1555:14
    frame #11: 0x000000010000b6e4 fizzy-integration-test`std::__1::__vector_base<fizzy::ValType, std::__1::allocator<fizzy::ValType> >::~__vector_base(this=0x00000001004053b0) at vector:465:9
    frame #12: 0x000000010000b5ba fizzy-integration-test`std::__1::vector<fizzy::ValType, std::__1::allocator<fizzy::ValType> >::~vector(this=0x00000001004053b0 size=0) at vector:556:5
    frame #13: 0x000000010000b585 fizzy-integration-test`std::__1::vector<fizzy::ValType, std::__1::allocator<fizzy::ValType> >::~vector(this=0x00000001004053b0 size=0) at vector:551:5
    frame #14: 0x000000010000b55c fizzy-integration-test`fizzy::FuncType::~FuncType(this=0x00000001004053b0) at types.hpp:30:8
    frame #15: 0x000000010000b525 fizzy-integration-test`fizzy::FuncType::~FuncType(this=0x00000001004053b0) at types.hpp:30:8
    frame #16: 0x000000010000b509 fizzy-integration-test`std::__1::allocator<fizzy::FuncType>::destroy(this=0x00000001004056e0, __p=0x00000001004053b0) at memory:1881:64
    frame #17: 0x000000010000b4dd fizzy-integration-test`void std::__1::allocator_traits<std::__1::allocator<fizzy::FuncType> >::__destroy<fizzy::FuncType>((null)=std::__1::true_type @ 0x00007ffeefbfeff8, __a=0x00000001004056e0, __p=0x00000001004053b0) at memory:1743:18
    frame #18: 0x000000010000b4ad fizzy-integration-test`void std::__1::allocator_traits<std::__1::allocator<fizzy::FuncType> >::destroy<fizzy::FuncType>(__a=0x00000001004056e0, __p=0x00000001004053b0) at memory:1596:14
    frame #19: 0x000000010000b468 fizzy-integration-test`std::__1::__vector_base<fizzy::FuncType, std::__1::allocator<fizzy::FuncType> >::__destruct_at_end(this=0x00000001004056d0, __new_last=0x00000001004053b0) at vector:427:9
    frame #20: 0x000000010000b3b8 fizzy-integration-test`std::__1::__vector_base<fizzy::FuncType, std::__1::allocator<fizzy::FuncType> >::clear(this=0x00000001004056d0) at vector:370:29
    frame #21: 0x000000010000b267 fizzy-integration-test`std::__1::__vector_base<fizzy::FuncType, std::__1::allocator<fizzy::FuncType> >::~__vector_base(this=0x00000001004056d0) at vector:464:9
    frame #22: 0x000000010000b15a fizzy-integration-test`std::__1::vector<fizzy::FuncType, std::__1::allocator<fizzy::FuncType> >::~vector(this=0x00000001004056d0 size=1) at vector:556:5
    frame #23: 0x000000010000a155 fizzy-integration-test`std::__1::vector<fizzy::FuncType, std::__1::allocator<fizzy::FuncType> >::~vector(this=0x00000001004056d0 size=1) at vector:551:5
    frame #24: 0x000000010000a0cc fizzy-integration-test`fizzy::Module::~Module(this=0x00000001004056d0) at module.hpp:14:8
    frame #25: 0x0000000100008dc5 fizzy-integration-test`fizzy::Module::~Module(this=0x00000001004056d0) at module.hpp:14:8
    frame #26: 0x0000000100016f1b fizzy-integration-test`std::__1::default_delete<fizzy::Module const>::operator(this=0x0000000100504080, __ptr=0x00000001004056d0)(fizzy::Module const*) const at memory:2339:5
    frame #27: 0x0000000100016ebf fizzy-integration-test`std::__1::unique_ptr<fizzy::Module const, std::__1::default_delete<fizzy::Module const> >::reset(this=0x0000000100504080, __p=0x0000000000000000) at memory:2652:7
    frame #28: 0x0000000100016e59 fizzy-integration-test`std::__1::unique_ptr<fizzy::Module const, std::__1::default_delete<fizzy::Module const> >::~unique_ptr(this=0x0000000100504080) at memory:2606:19
    frame #29: 0x0000000100008c25 fizzy-integration-test`std::__1::unique_ptr<fizzy::Module const, std::__1::default_delete<fizzy::Module const> >::~unique_ptr(this=0x0000000100504080) at memory:2606:17
    frame #30: 0x00000001000161dc fizzy-integration-test`fizzy::Instance::~Instance(this=0x0000000100504080) at instantiate.hpp:82:8
    frame #31: 0x0000000100009de5 fizzy-integration-test`fizzy::Instance::~Instance(this=0x0000000100504080) at instantiate.hpp:82:8
    frame #32: 0x0000000100009dbc fizzy-integration-test`::fizzy_free_instance(instance=0x0000000100504080) at capi.cpp:558:5
    frame #33: 0x00000001000057a1 fizzy-integration-test`_$LT$fizzy..Instance$u20$as$u20$core..ops..drop..Drop$GT$::drop::h886bfb910d6ff66a(self=0x00007ffeefbff310) at lib.rs:60:18
    frame #34: 0x00000001000011f1 fizzy-integration-test`core::ptr::drop_in_place::hd1c931065015e10f((null)=0x00007ffeefbff310) at mod.rs:175:1
    frame #35: 0x0000000100001600 fizzy-integration-test`fizzy_integration_test::main::h7ea1d6484d7de259 at main.rs:33:1
    frame #36: 0x000000010000118e fizzy-integration-test`core::ops::function::FnOnce::call_once::ha0d3047fb68cd523((null)=(fizzy-integration-test`fizzy_integration_test::main::h7ea1d6484d7de259 at main.rs:7), (null)=<unavailable>) at function.rs:227:5
    frame #37: 0x00000001000016b1 fizzy-integration-test`std::sys_common::backtrace::__rust_begin_short_backtrace::hdf5bb73bc506fc48(f=(fizzy-integration-test`fizzy_integration_test::main::h7ea1d6484d7de259 at main.rs:7)) at backtrace.rs:125:18
    frame #38: 0x0000000100001744 fizzy-integration-test`std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::h1ee7801da914b482 at rt.rs:66:18
    frame #39: 0x000000010008a084 fizzy-integration-test`std::rt::lang_start_internal::h36ccce6e8a047133 [inlined] core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$F$GT$::call_once::h81f763a559f81b5c at function.rs:259:13 [opt]
    frame #40: 0x000000010008a07d fizzy-integration-test`std::rt::lang_start_internal::h36ccce6e8a047133 [inlined] std::panicking::try::do_call::h8f7e7501b4b6c841 at panicking.rs:381 [opt]
    frame #41: 0x000000010008a07d fizzy-integration-test`std::rt::lang_start_internal::h36ccce6e8a047133 [inlined] std::panicking::try::h5def58989e0f2c84 at panicking.rs:345 [opt]
    frame #42: 0x000000010008a07d fizzy-integration-test`std::rt::lang_start_internal::h36ccce6e8a047133 [inlined] std::panic::catch_unwind::h8210e1d7d92e8f91 at panic.rs:396 [opt]
    frame #43: 0x000000010008a07d fizzy-integration-test`std::rt::lang_start_internal::h36ccce6e8a047133 at rt.rs:51 [opt]
    frame #44: 0x0000000100001721 fizzy-integration-test`std::rt::lang_start::h0f0b19eee08fa02f(main=(fizzy-integration-test`fizzy_integration_test::main::h7ea1d6484d7de259 at main.rs:7), argc=1, argv=0x00007ffeefbff4e0) at rt.rs:65:5
    frame #45: 0x0000000100001652 fizzy-integration-test`main + 34
    frame #46: 0x00007fff6e7b7cc9 libdyld.dylib`start + 1

[axic]

Previous issue fixed by #725.

[axic]

I think the public C API we have accomplishes this goal already.

[gumb0]

Looks fine, but CI failed.

[axic]

Looks fine, but CI failed.

Because cargo doc executes the example and it seems somehow we need to pass it flags for ASan.