aws_sdk_lambda/operation/
get_function_concurrency.rs

1// Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
2/// Orchestration and serialization glue logic for `GetFunctionConcurrency`.
3#[derive(::std::clone::Clone, ::std::default::Default, ::std::fmt::Debug)]
4#[non_exhaustive]
5pub struct GetFunctionConcurrency;
6impl GetFunctionConcurrency {
7    /// Creates a new `GetFunctionConcurrency`
8    pub fn new() -> Self {
9        Self
10    }
11    pub(crate) async fn orchestrate(
12        runtime_plugins: &::aws_smithy_runtime_api::client::runtime_plugin::RuntimePlugins,
13        input: crate::operation::get_function_concurrency::GetFunctionConcurrencyInput,
14    ) -> ::std::result::Result<
15        crate::operation::get_function_concurrency::GetFunctionConcurrencyOutput,
16        ::aws_smithy_runtime_api::client::result::SdkError<
17            crate::operation::get_function_concurrency::GetFunctionConcurrencyError,
18            ::aws_smithy_runtime_api::client::orchestrator::HttpResponse,
19        >,
20    > {
21        let map_err = |err: ::aws_smithy_runtime_api::client::result::SdkError<
22            ::aws_smithy_runtime_api::client::interceptors::context::Error,
23            ::aws_smithy_runtime_api::client::orchestrator::HttpResponse,
24        >| {
25            err.map_service_error(|err| {
26                err.downcast::<crate::operation::get_function_concurrency::GetFunctionConcurrencyError>()
27                    .expect("correct error type")
28            })
29        };
30        let context = Self::orchestrate_with_stop_point(runtime_plugins, input, ::aws_smithy_runtime::client::orchestrator::StopPoint::None)
31            .await
32            .map_err(map_err)?;
33        let output = context.finalize().map_err(map_err)?;
34        ::std::result::Result::Ok(
35            output
36                .downcast::<crate::operation::get_function_concurrency::GetFunctionConcurrencyOutput>()
37                .expect("correct output type"),
38        )
39    }
40
41    pub(crate) async fn orchestrate_with_stop_point(
42        runtime_plugins: &::aws_smithy_runtime_api::client::runtime_plugin::RuntimePlugins,
43        input: crate::operation::get_function_concurrency::GetFunctionConcurrencyInput,
44        stop_point: ::aws_smithy_runtime::client::orchestrator::StopPoint,
45    ) -> ::std::result::Result<
46        ::aws_smithy_runtime_api::client::interceptors::context::InterceptorContext,
47        ::aws_smithy_runtime_api::client::result::SdkError<
48            ::aws_smithy_runtime_api::client::interceptors::context::Error,
49            ::aws_smithy_runtime_api::client::orchestrator::HttpResponse,
50        >,
51    > {
52        let input = ::aws_smithy_runtime_api::client::interceptors::context::Input::erase(input);
53        use ::tracing::Instrument;
54        ::aws_smithy_runtime::client::orchestrator::invoke_with_stop_point("Lambda", "GetFunctionConcurrency", input, runtime_plugins, stop_point)
55            // Create a parent span for the entire operation. Includes a random, internal-only,
56            // seven-digit ID for the operation orchestration so that it can be correlated in the logs.
57            .instrument(::tracing::debug_span!(
58                "Lambda.GetFunctionConcurrency",
59                "rpc.service" = "Lambda",
60                "rpc.method" = "GetFunctionConcurrency",
61                "sdk_invocation_id" = ::fastrand::u32(1_000_000..10_000_000),
62                "rpc.system" = "aws-api",
63            ))
64            .await
65    }
66
67    pub(crate) fn operation_runtime_plugins(
68        client_runtime_plugins: ::aws_smithy_runtime_api::client::runtime_plugin::RuntimePlugins,
69        client_config: &crate::config::Config,
70        config_override: ::std::option::Option<crate::config::Builder>,
71    ) -> ::aws_smithy_runtime_api::client::runtime_plugin::RuntimePlugins {
72        let mut runtime_plugins = client_runtime_plugins.with_operation_plugin(Self::new());
73
74        if let ::std::option::Option::Some(config_override) = config_override {
75            for plugin in config_override.runtime_plugins.iter().cloned() {
76                runtime_plugins = runtime_plugins.with_operation_plugin(plugin);
77            }
78            runtime_plugins = runtime_plugins.with_operation_plugin(crate::config::ConfigOverrideRuntimePlugin::new(
79                config_override,
80                client_config.config.clone(),
81                &client_config.runtime_components,
82            ));
83        }
84        runtime_plugins
85    }
86}
87impl ::aws_smithy_runtime_api::client::runtime_plugin::RuntimePlugin for GetFunctionConcurrency {
88    fn config(&self) -> ::std::option::Option<::aws_smithy_types::config_bag::FrozenLayer> {
89        let mut cfg = ::aws_smithy_types::config_bag::Layer::new("GetFunctionConcurrency");
90
91        cfg.store_put(::aws_smithy_runtime_api::client::ser_de::SharedRequestSerializer::new(
92            GetFunctionConcurrencyRequestSerializer,
93        ));
94        cfg.store_put(::aws_smithy_runtime_api::client::ser_de::SharedResponseDeserializer::new(
95            GetFunctionConcurrencyResponseDeserializer,
96        ));
97
98        cfg.store_put(::aws_smithy_runtime_api::client::auth::AuthSchemeOptionResolverParams::new(
99            crate::config::auth::Params::builder()
100                .operation_name("GetFunctionConcurrency")
101                .build()
102                .expect("required fields set"),
103        ));
104
105        cfg.store_put(::aws_smithy_runtime_api::client::orchestrator::Metadata::new(
106            "GetFunctionConcurrency",
107            "Lambda",
108        ));
109        let mut signing_options = ::aws_runtime::auth::SigningOptions::default();
110        signing_options.double_uri_encode = true;
111        signing_options.content_sha256_header = false;
112        signing_options.normalize_uri_path = true;
113        signing_options.payload_override = None;
114
115        cfg.store_put(::aws_runtime::auth::SigV4OperationSigningConfig {
116            signing_options,
117            ..::std::default::Default::default()
118        });
119
120        ::std::option::Option::Some(cfg.freeze())
121    }
122
123    fn runtime_components(
124        &self,
125        _: &::aws_smithy_runtime_api::client::runtime_components::RuntimeComponentsBuilder,
126    ) -> ::std::borrow::Cow<'_, ::aws_smithy_runtime_api::client::runtime_components::RuntimeComponentsBuilder> {
127        #[allow(unused_mut)]
128        let mut rcb = ::aws_smithy_runtime_api::client::runtime_components::RuntimeComponentsBuilder::new("GetFunctionConcurrency")
129            .with_interceptor(::aws_smithy_runtime_api::client::interceptors::SharedInterceptor::permanent(
130                GetFunctionConcurrencyTelemetryInputCaptureInterceptor,
131            ))
132            .with_interceptor(::aws_smithy_runtime_api::client::interceptors::SharedInterceptor::permanent(
133                ::aws_smithy_runtime::client::stalled_stream_protection::StalledStreamProtectionInterceptor::default(),
134            ))
135            .with_interceptor(::aws_smithy_runtime_api::client::interceptors::SharedInterceptor::permanent(
136                GetFunctionConcurrencyEndpointParamsInterceptor,
137            ))
138            .with_retry_classifier(::aws_smithy_runtime::client::retries::classifiers::TransientErrorClassifier::<
139                crate::operation::get_function_concurrency::GetFunctionConcurrencyError,
140            >::new())
141            .with_retry_classifier(::aws_smithy_runtime::client::retries::classifiers::ModeledAsRetryableClassifier::<
142                crate::operation::get_function_concurrency::GetFunctionConcurrencyError,
143            >::new())
144            .with_retry_classifier(::aws_runtime::retries::classifiers::AwsErrorCodeClassifier::<
145                crate::operation::get_function_concurrency::GetFunctionConcurrencyError,
146            >::new())
147            .with_retry_classifier(::aws_runtime::service_clock_skew::ServiceClockSkewClassifier::<
148                crate::operation::get_function_concurrency::GetFunctionConcurrencyError,
149            >::new());
150
151        ::std::borrow::Cow::Owned(rcb)
152    }
153}
154
155#[derive(Debug)]
156struct GetFunctionConcurrencyTelemetryInputCaptureInterceptor;
157
158#[::aws_smithy_runtime_api::client::interceptors::dyn_dispatch_hint]
159impl ::aws_smithy_runtime_api::client::interceptors::Intercept for GetFunctionConcurrencyTelemetryInputCaptureInterceptor {
160    fn name(&self) -> &'static str {
161        "GetFunctionConcurrencyTelemetryInputCaptureInterceptor"
162    }
163
164    fn read_before_execution(
165        &self,
166        context: &::aws_smithy_runtime_api::client::interceptors::context::BeforeSerializationInterceptorContextRef<
167            '_,
168            ::aws_smithy_runtime_api::client::interceptors::context::Input,
169            ::aws_smithy_runtime_api::client::interceptors::context::Output,
170            ::aws_smithy_runtime_api::client::interceptors::context::Error,
171        >,
172        cfg: &mut ::aws_smithy_types::config_bag::ConfigBag,
173    ) -> ::std::result::Result<(), ::aws_smithy_runtime_api::box_error::BoxError> {
174        // Nothing to do unless the customer opted in by naming members to record.
175        let ::std::option::Option::Some(requested) = cfg
176            .load::<::aws_smithy_types::telemetry::RequestedTelemetryAttributes>()
177            .filter(|r| !r.is_empty())
178        else {
179            return ::std::result::Result::Ok(());
180        };
181
182        let ::std::option::Option::Some(input) = context.input().downcast_ref::<GetFunctionConcurrencyInput>() else {
183            // A mismatched input is not this interceptor's concern; skip quietly.
184            return ::std::result::Result::Ok(());
185        };
186
187        let mut captured = ::aws_smithy_types::telemetry::CapturedTelemetryAttributes::default();
188        if requested.should_capture("FunctionName") {
189            if let ::std::option::Option::Some(value) = input.function_name.as_deref() {
190                captured.insert("FunctionName", value);
191            }
192        }
193
194        cfg.interceptor_state().store_put(captured);
195        ::std::result::Result::Ok(())
196    }
197}
198#[derive(Debug)]
199struct GetFunctionConcurrencyResponseDeserializer;
200impl ::aws_smithy_runtime_api::client::ser_de::DeserializeResponse for GetFunctionConcurrencyResponseDeserializer {
201    fn deserialize_nonstreaming_with_config(
202        &self,
203        response: &::aws_smithy_runtime_api::client::orchestrator::HttpResponse,
204        _cfg: &::aws_smithy_types::config_bag::ConfigBag,
205    ) -> ::aws_smithy_runtime_api::client::interceptors::context::OutputOrError {
206        let (success, status) = (response.status().is_success(), response.status().as_u16());
207        let headers = response.headers();
208        let body = response.body().bytes().expect("body loaded");
209        #[allow(unused_mut)]
210        let mut force_error = false;
211        ::tracing::debug!(request_id = ?::aws_types::request_id::RequestId::request_id(response));
212        let parse_result = if !success && status != 200 || force_error {
213            crate::protocol_serde::shape_get_function_concurrency::de_get_function_concurrency_http_error(status, headers, body)
214        } else {
215            crate::protocol_serde::shape_get_function_concurrency::de_get_function_concurrency_http_response(status, headers, body)
216        };
217        crate::protocol_serde::type_erase_result(parse_result)
218    }
219}
220#[derive(Debug)]
221struct GetFunctionConcurrencyRequestSerializer;
222impl ::aws_smithy_runtime_api::client::ser_de::SerializeRequest for GetFunctionConcurrencyRequestSerializer {
223    #[allow(unused_mut, clippy::let_and_return, clippy::needless_borrow, clippy::useless_conversion)]
224    fn serialize_input(
225        &self,
226        input: ::aws_smithy_runtime_api::client::interceptors::context::Input,
227        _cfg: &mut ::aws_smithy_types::config_bag::ConfigBag,
228    ) -> ::std::result::Result<::aws_smithy_runtime_api::client::orchestrator::HttpRequest, ::aws_smithy_runtime_api::box_error::BoxError> {
229        let input = input
230            .downcast::<crate::operation::get_function_concurrency::GetFunctionConcurrencyInput>()
231            .expect("correct type");
232        let _header_serialization_settings = _cfg
233            .load::<crate::serialization_settings::HeaderSerializationSettings>()
234            .cloned()
235            .unwrap_or_default();
236        let mut request_builder = {
237            #[allow(clippy::uninlined_format_args)]
238            fn uri_base(
239                _input: &crate::operation::get_function_concurrency::GetFunctionConcurrencyInput,
240                output: &mut ::std::string::String,
241            ) -> ::std::result::Result<(), ::aws_smithy_types::error::operation::BuildError> {
242                use ::std::fmt::Write as _;
243                let input_1 = &_input.function_name;
244                let input_1 = input_1
245                    .as_ref()
246                    .ok_or_else(|| ::aws_smithy_types::error::operation::BuildError::missing_field("function_name", "cannot be empty or unset"))?;
247                let function_name = ::aws_smithy_http::label::fmt_string(input_1, ::aws_smithy_http::label::EncodingStrategy::Default);
248                if function_name.is_empty() {
249                    return ::std::result::Result::Err(::aws_smithy_types::error::operation::BuildError::missing_field(
250                        "function_name",
251                        "cannot be empty or unset",
252                    ));
253                }
254                ::std::write!(output, "/2019-09-30/functions/{FunctionName}/concurrency", FunctionName = function_name)
255                    .expect("formatting should succeed");
256                ::std::result::Result::Ok(())
257            }
258            #[allow(clippy::unnecessary_wraps)]
259            fn update_http_builder(
260                input: &crate::operation::get_function_concurrency::GetFunctionConcurrencyInput,
261                builder: ::http_1x::request::Builder,
262            ) -> ::std::result::Result<::http_1x::request::Builder, ::aws_smithy_types::error::operation::BuildError> {
263                let mut uri = ::std::string::String::new();
264                uri_base(input, &mut uri)?;
265                ::std::result::Result::Ok(builder.method("GET").uri(uri))
266            }
267            let mut builder = update_http_builder(&input, ::http_1x::request::Builder::new())?;
268            builder
269        };
270        let body = ::aws_smithy_types::body::SdkBody::from("");
271
272        ::std::result::Result::Ok(request_builder.body(body).expect("valid request").try_into().unwrap())
273    }
274}
275#[derive(Debug)]
276struct GetFunctionConcurrencyEndpointParamsInterceptor;
277
278#[::aws_smithy_runtime_api::client::interceptors::dyn_dispatch_hint]
279impl ::aws_smithy_runtime_api::client::interceptors::Intercept for GetFunctionConcurrencyEndpointParamsInterceptor {
280    fn name(&self) -> &'static str {
281        "GetFunctionConcurrencyEndpointParamsInterceptor"
282    }
283
284    fn read_before_execution(
285        &self,
286        context: &::aws_smithy_runtime_api::client::interceptors::context::BeforeSerializationInterceptorContextRef<
287            '_,
288            ::aws_smithy_runtime_api::client::interceptors::context::Input,
289            ::aws_smithy_runtime_api::client::interceptors::context::Output,
290            ::aws_smithy_runtime_api::client::interceptors::context::Error,
291        >,
292        cfg: &mut ::aws_smithy_types::config_bag::ConfigBag,
293    ) -> ::std::result::Result<(), ::aws_smithy_runtime_api::box_error::BoxError> {
294        let _input = context
295            .input()
296            .downcast_ref::<GetFunctionConcurrencyInput>()
297            .ok_or("failed to downcast to GetFunctionConcurrencyInput")?;
298
299        let params = crate::config::endpoint::Params::builder()
300            .set_region(cfg.load::<::aws_types::region::Region>().map(|r| r.as_ref().to_owned()))
301            .set_use_dual_stack(cfg.load::<::aws_types::endpoint_config::UseDualStack>().map(|ty| ty.0))
302            .set_use_fips(cfg.load::<::aws_types::endpoint_config::UseFips>().map(|ty| ty.0))
303            .set_endpoint(cfg.load::<::aws_types::endpoint_config::EndpointUrl>().map(|ty| ty.0.clone()))
304            .build()
305            .map_err(|err| {
306                ::aws_smithy_runtime_api::client::interceptors::error::ContextAttachedError::new("endpoint params could not be built", err)
307            })?;
308        cfg.interceptor_state()
309            .store_put(::aws_smithy_runtime_api::client::endpoint::EndpointResolverParams::new(params));
310        ::std::result::Result::Ok(())
311    }
312}
313
314// The get_* functions below are generated from JMESPath expressions in the
315// operationContextParams trait. They target the operation's input shape.
316
317/// Error type for the `GetFunctionConcurrencyError` operation.
318#[non_exhaustive]
319#[derive(::std::fmt::Debug)]
320pub enum GetFunctionConcurrencyError {
321    /// <p>One of the parameters in the request is not valid.</p>
322    InvalidParameterValueException(crate::types::error::InvalidParameterValueException),
323    /// <p>The resource specified in the request does not exist.</p>
324    ResourceNotFoundException(crate::types::error::ResourceNotFoundException),
325    /// <p>The Lambda service encountered an internal error.</p>
326    ServiceException(crate::types::error::ServiceException),
327    /// <p>The request throughput limit was exceeded. For more information, see <a href="https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html#api-requests">Lambda quotas</a>.</p>
328    TooManyRequestsException(crate::types::error::TooManyRequestsException),
329    /// An unexpected error occurred (e.g., invalid JSON returned by the service or an unknown error code).
330    #[deprecated(note = "Matching `Unhandled` directly is not forwards compatible. Instead, match using a \
331    variable wildcard pattern and check `.code()`:
332     \
333    &nbsp;&nbsp;&nbsp;`err if err.code() == Some(\"SpecificExceptionCode\") => { /* handle the error */ }`
334     \
335    See [`ProvideErrorMetadata`](#impl-ProvideErrorMetadata-for-GetFunctionConcurrencyError) for what information is available for the error.")]
336    Unhandled(crate::error::sealed_unhandled::Unhandled),
337}
338impl GetFunctionConcurrencyError {
339    /// Creates the `GetFunctionConcurrencyError::Unhandled` variant from any error type.
340    pub fn unhandled(
341        err: impl ::std::convert::Into<::std::boxed::Box<dyn ::std::error::Error + ::std::marker::Send + ::std::marker::Sync + 'static>>,
342    ) -> Self {
343        Self::Unhandled(crate::error::sealed_unhandled::Unhandled {
344            source: err.into(),
345            meta: ::std::default::Default::default(),
346        })
347    }
348
349    /// Creates the `GetFunctionConcurrencyError::Unhandled` variant from an [`ErrorMetadata`](::aws_smithy_types::error::ErrorMetadata).
350    pub fn generic(err: ::aws_smithy_types::error::ErrorMetadata) -> Self {
351        Self::Unhandled(crate::error::sealed_unhandled::Unhandled {
352            source: err.clone().into(),
353            meta: err,
354        })
355    }
356    ///
357    /// Returns error metadata, which includes the error code, message,
358    /// request ID, and potentially additional information.
359    ///
360    pub fn meta(&self) -> &::aws_smithy_types::error::ErrorMetadata {
361        match self {
362            Self::InvalidParameterValueException(e) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(e),
363            Self::ResourceNotFoundException(e) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(e),
364            Self::ServiceException(e) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(e),
365            Self::TooManyRequestsException(e) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(e),
366            Self::Unhandled(e) => &e.meta,
367        }
368    }
369    /// Returns `true` if the error kind is `GetFunctionConcurrencyError::InvalidParameterValueException`.
370    pub fn is_invalid_parameter_value_exception(&self) -> bool {
371        matches!(self, Self::InvalidParameterValueException(_))
372    }
373    /// Returns `true` if the error kind is `GetFunctionConcurrencyError::ResourceNotFoundException`.
374    pub fn is_resource_not_found_exception(&self) -> bool {
375        matches!(self, Self::ResourceNotFoundException(_))
376    }
377    /// Returns `true` if the error kind is `GetFunctionConcurrencyError::ServiceException`.
378    pub fn is_service_exception(&self) -> bool {
379        matches!(self, Self::ServiceException(_))
380    }
381    /// Returns `true` if the error kind is `GetFunctionConcurrencyError::TooManyRequestsException`.
382    pub fn is_too_many_requests_exception(&self) -> bool {
383        matches!(self, Self::TooManyRequestsException(_))
384    }
385}
386impl ::std::error::Error for GetFunctionConcurrencyError {
387    fn source(&self) -> ::std::option::Option<&(dyn ::std::error::Error + 'static)> {
388        match self {
389            Self::InvalidParameterValueException(_inner) => ::std::option::Option::Some(_inner),
390            Self::ResourceNotFoundException(_inner) => ::std::option::Option::Some(_inner),
391            Self::ServiceException(_inner) => ::std::option::Option::Some(_inner),
392            Self::TooManyRequestsException(_inner) => ::std::option::Option::Some(_inner),
393            Self::Unhandled(_inner) => ::std::option::Option::Some(&*_inner.source),
394        }
395    }
396}
397impl ::std::fmt::Display for GetFunctionConcurrencyError {
398    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
399        match self {
400            Self::InvalidParameterValueException(_inner) => _inner.fmt(f),
401            Self::ResourceNotFoundException(_inner) => _inner.fmt(f),
402            Self::ServiceException(_inner) => _inner.fmt(f),
403            Self::TooManyRequestsException(_inner) => _inner.fmt(f),
404            Self::Unhandled(_inner) => {
405                if let ::std::option::Option::Some(code) = ::aws_smithy_types::error::metadata::ProvideErrorMetadata::code(self) {
406                    write!(f, "unhandled error ({code})")
407                } else {
408                    f.write_str("unhandled error")
409                }
410            }
411        }
412    }
413}
414impl ::aws_smithy_types::retry::ProvideErrorKind for GetFunctionConcurrencyError {
415    fn code(&self) -> ::std::option::Option<&str> {
416        ::aws_smithy_types::error::metadata::ProvideErrorMetadata::code(self)
417    }
418    fn retryable_error_kind(&self) -> ::std::option::Option<::aws_smithy_types::retry::ErrorKind> {
419        ::std::option::Option::None
420    }
421}
422impl ::aws_smithy_types::error::metadata::ProvideErrorMetadata for GetFunctionConcurrencyError {
423    fn meta(&self) -> &::aws_smithy_types::error::ErrorMetadata {
424        match self {
425            Self::InvalidParameterValueException(_inner) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(_inner),
426            Self::ResourceNotFoundException(_inner) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(_inner),
427            Self::ServiceException(_inner) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(_inner),
428            Self::TooManyRequestsException(_inner) => ::aws_smithy_types::error::metadata::ProvideErrorMetadata::meta(_inner),
429            Self::Unhandled(_inner) => &_inner.meta,
430        }
431    }
432}
433impl ::aws_smithy_runtime_api::client::result::CreateUnhandledError for GetFunctionConcurrencyError {
434    fn create_unhandled_error(
435        source: ::std::boxed::Box<dyn ::std::error::Error + ::std::marker::Send + ::std::marker::Sync + 'static>,
436        meta: ::std::option::Option<::aws_smithy_types::error::ErrorMetadata>,
437    ) -> Self {
438        Self::Unhandled(crate::error::sealed_unhandled::Unhandled {
439            source,
440            meta: meta.unwrap_or_default(),
441        })
442    }
443}
444impl ::aws_types::request_id::RequestId for crate::operation::get_function_concurrency::GetFunctionConcurrencyError {
445    fn request_id(&self) -> Option<&str> {
446        self.meta().request_id()
447    }
448}
449
450pub use crate::operation::get_function_concurrency::_get_function_concurrency_input::GetFunctionConcurrencyInput;
451
452pub use crate::operation::get_function_concurrency::_get_function_concurrency_output::GetFunctionConcurrencyOutput;
453
454mod _get_function_concurrency_input;
455
456mod _get_function_concurrency_output;
457
458/// Builders
459pub mod builders;
aws_sdk_lambda/operation/get_function_concurrency.rs

aws_sdk_lambda/operation/
get_function_concurrency.rs
