Enable the tokio-rt feature for generated crates when bytestream is used (#3113)

## Motivation and Context
Fix issue where `ByteStream::from_path` was unusable by without enabling
features

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

---------

Co-authored-by: ysaito1001 <[email protected]>

Author: rcoh

aws/sdk/integration-tests/s3/tests/client_construction.rs

@@ -26,6 +26,11 @@ mod with_sdk_config {
         assert!(config.retry_config().is_none());
         let _s3 = s3::Client::new(&config);
     }
+
+    #[test]
+    fn bytestream_from_path_exists() {
+        let _ = aws_sdk_s3::primitives::ByteStream::from_path("a/b.txt");
+    }
 }
 
 mod with_service_config {

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/customize/RequiredCustomizations.kt

@@ -86,7 +86,7 @@ class RequiredCustomizations : ClientCodegenDecorator {
         ResiliencyReExportCustomization(codegenContext).extras(rustCrate)
 
         rustCrate.withModule(ClientRustModule.Primitives) {
-            pubUseSmithyPrimitives(codegenContext, codegenContext.model)(this)
+            pubUseSmithyPrimitives(codegenContext, codegenContext.model, rustCrate)(this)
         }
         rustCrate.withModule(ClientRustModule.Error) {
             rustTemplate(

codegen-core/src/main/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customizations/SmithyTypesPubUseExtra.kt

@@ -8,11 +8,13 @@ package software.amazon.smithy.rust.codegen.core.smithy.customizations
 import software.amazon.smithy.model.Model
 import software.amazon.smithy.model.shapes.Shape
 import software.amazon.smithy.model.shapes.StructureShape
+import software.amazon.smithy.rust.codegen.core.rustlang.Feature
 import software.amazon.smithy.rust.codegen.core.rustlang.Writable
 import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
 import software.amazon.smithy.rust.codegen.core.rustlang.writable
 import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
 import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
+import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
 import software.amazon.smithy.rust.codegen.core.util.hasEventStreamMember
 import software.amazon.smithy.rust.codegen.core.util.hasStreamingMember
 
@@ -41,7 +43,7 @@ private fun hasBlobs(model: Model): Boolean = structUnionMembersMatchPredicate(m
 private fun hasDateTimes(model: Model): Boolean = structUnionMembersMatchPredicate(model, Shape::isTimestampShape)
 
 /** Adds re-export statements for Smithy primitives */
-fun pubUseSmithyPrimitives(codegenContext: CodegenContext, model: Model): Writable = writable {
+fun pubUseSmithyPrimitives(codegenContext: CodegenContext, model: Model, rustCrate: RustCrate): Writable = writable {
     val rc = codegenContext.runtimeConfig
     if (hasBlobs(model)) {
         rustTemplate("pub use #{Blob};", "Blob" to RuntimeType.blob(rc))
@@ -57,6 +59,13 @@ fun pubUseSmithyPrimitives(codegenContext: CodegenContext, model: Model): Writab
         )
     }
     if (hasStreamingOperations(model)) {
+        rustCrate.mergeFeature(
+            Feature(
+                "rt-tokio",
+                true,
+                listOf("aws-smithy-types/rt-tokio"),
+            ),
+        )
         rustTemplate(
             """
             pub use #{ByteStream};

codegen-core/src/test/kotlin/software/amazon/smithy/rust/codegen/core/smithy/customizations/SmithyTypesPubUseExtraTest.kt

@@ -8,8 +8,11 @@ package software.amazon.smithy.rust.codegen.core.smithy.customizations
 import org.junit.jupiter.api.Test
 import software.amazon.smithy.model.Model
 import software.amazon.smithy.rust.codegen.core.rustlang.RustWriter
+import software.amazon.smithy.rust.codegen.core.smithy.CodegenContext
+import software.amazon.smithy.rust.codegen.core.smithy.RustCrate
 import software.amazon.smithy.rust.codegen.core.smithy.generators.StructureGeneratorTest.Companion.model
 import software.amazon.smithy.rust.codegen.core.testutil.asSmithyModel
+import software.amazon.smithy.rust.codegen.core.testutil.generatePluginContext
 import software.amazon.smithy.rust.codegen.core.testutil.testCodegenContext
 
 class SmithyTypesPubUseExtraTest {
@@ -43,14 +46,34 @@ class SmithyTypesPubUseExtraTest {
         """.asSmithyModel()
     }
 
+    private val rustCrate: RustCrate
+    private val codegenContext: CodegenContext = testCodegenContext(model)
+
+    init {
+        val (context, _) = generatePluginContext(
+            model,
+            runtimeConfig = codegenContext.runtimeConfig,
+        )
+        rustCrate = RustCrate(
+            context.fileManifest,
+            codegenContext.symbolProvider,
+            codegenContext.settings.codegenConfig,
+            codegenContext.expectModuleDocProvider(),
+        )
+    }
+
     private fun reexportsWithEmptyModel() = reexportsWithMember()
     private fun reexportsWithMember(
         inputMember: String = "",
         outputMember: String = "",
         unionMember: String = "",
         additionalShape: String = "",
     ) = RustWriter.root().let { writer ->
-        pubUseSmithyPrimitives(testCodegenContext(model), modelWithMember(inputMember, outputMember, unionMember, additionalShape))(writer)
+        pubUseSmithyPrimitives(
+            codegenContext,
+            modelWithMember(inputMember, outputMember, unionMember, additionalShape),
+            rustCrate,
+        )(writer)
         writer.toString()
     }
 

codegen-server/src/main/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/ServerRequiredCustomizations.kt

@@ -47,7 +47,7 @@ class ServerRequiredCustomizations : ServerCodegenDecorator {
         )
 
         rustCrate.withModule(ServerRustModule.Types) {
-            pubUseSmithyPrimitives(codegenContext, codegenContext.model)(this)
+            pubUseSmithyPrimitives(codegenContext, codegenContext.model, rustCrate)(this)
             rustTemplate(
                 """
                 pub use #{DisplayErrorContext};