Add Clone impl to PresignedRequest (#3084)

## Motivation and Context
This makes it easier to convert presigned request into an HTTP request

## Description
<!--- Describe your changes in detail -->
- add clone impl
- add `make_presigned_request` that borrows from self

## Testing
CI
## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [ ] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates
- [ ] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

----

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copy, and redistribute this contribution, under the terms of your
choice._

aws/rust-runtime/aws-inlineable/src/presigning.rs

@@ -14,6 +14,7 @@
 
 use aws_smithy_runtime_api::box_error::BoxError;
 use aws_smithy_runtime_api::client::orchestrator::HttpRequest;
+use aws_smithy_types::body::SdkBody;
 use std::fmt;
 use std::time::{Duration, SystemTime};
 
@@ -170,37 +171,70 @@ impl PresigningConfigBuilder {
 ///
 /// **This struct has conversion convenience functions:**
 ///
-/// - [`PresignedRequest::to_http_02x_request<B>`][Self::to_http_02x_request] returns an [`http::Request<B>`](https://docs.rs/http/0.2.6/http/request/struct.Request.html)
+/// - [`PresignedRequest::make_http_02x_request<B>`][Self::make_http_02x_request] returns an [`http::Request<B>`](https://docs.rs/http/0.2.6/http/request/struct.Request.html)
 /// - [`PresignedRequest::into`](#impl-From<PresignedRequest>) returns an [`http::request::Builder`](https://docs.rs/http/0.2.6/http/request/struct.Builder.html)
 #[non_exhaustive]
-pub struct PresignedRequest(HttpRequest);
+pub struct PresignedRequest {
+    http_request: HttpRequest,
+}
+
+impl Clone for PresignedRequest {
+    fn clone(&self) -> Self {
+        Self {
+            http_request: match self.http_request.try_clone() {
+                Some(body) => body,
+                None => {
+                    unreachable!(
+                        "during construction, we replaced the body with `SdkBody::empty()`"
+                    )
+                }
+            },
+        }
+    }
+}
 
 impl PresignedRequest {
     #[allow(dead_code)]
-    pub(crate) fn new(inner: HttpRequest) -> Self {
-        Self(inner)
+    pub(crate) fn new(inner: HttpRequest) -> Result<Self, BoxError> {
+        // throw out the body so we're sure it's cloneable
+        let http_request = inner.map(|_body| SdkBody::empty());
+        // this should never fail, a presigned request should always be convertible, but better to
+        // protect against this potential panic
+        let _ = http_request
+            .try_clone()
+            .expect("must be cloneable, body is empty")
+            .into_http02x()?;
+        Ok(Self { http_request })
     }
 
     /// Returns the HTTP request method.
     pub fn method(&self) -> &str {
-        self.0.method()
+        self.http_request.method()
     }
 
     /// Returns the HTTP request URI.
     pub fn uri(&self) -> &str {
-        self.0.uri()
+        self.http_request.uri()
     }
 
     /// Returns any HTTP headers that need to go along with the request, except for `Host`,
     /// which should be sent based on the endpoint in the URI by the HTTP client rather than
     /// added directly.
     pub fn headers(&self) -> impl Iterator<Item = (&str, &str)> {
-        self.0.headers().iter()
+        self.http_request.headers().iter()
+    }
+
+    /// Given a body, produce an `http::Request` from this `PresignedRequest`
+    pub fn make_http_02x_request<B>(&self, body: B) -> http::Request<B> {
+        self.clone().into_http_02x_request(body)
     }
 
-    /// Given a body, convert this `PresignedRequest` into an `http::Request`
-    pub fn to_http_02x_request<B>(self, body: B) -> Result<http::Request<B>, BoxError> {
-        Ok(self.0.into_http02x()?.map(|_req| body))
+    /// Converts this `PresignedRequest` directly into an `http` request.
+    pub fn into_http_02x_request<B>(self, body: B) -> http::Request<B> {
+        self.http_request
+            .into_http02x()
+            .expect("constructor validated convertibility")
+            .map(|_req| body)
     }
 }
 
@@ -209,7 +243,7 @@ impl fmt::Debug for PresignedRequest {
         f.debug_struct("PresignedRequest")
             .field("method", &self.method())
             .field("uri", &self.uri())
-            .field("headers", self.0.headers())
+            .field("headers", self.http_request.headers())
             .finish()
     }
 }

aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/AwsPresigningDecorator.kt

@@ -185,7 +185,7 @@ class AwsPresignedFluentBuilderMethod(
                     })
                 })?;
             let request = context.take_request().expect("request set before transmit");
-            Ok(#{PresignedRequest}::new(request))
+            #{PresignedRequest}::new(request).map_err(#{SdkError}::construction_failure)
             """,
             *codegenScope,
             "Operation" to codegenContext.symbolProvider.toSymbol(section.operationShape),