Add nightly only into_future feature

Author: rylev

sdk/data_cosmos/Cargo.toml

@@ -43,3 +43,4 @@ stop-token = { version = "0.7.0", features = ["tokio"] }
 [features]
 test_e2e = []
 mock_transport_framework = [ "azure_core/mock_transport_framework"]
+into_future = []

sdk/data_cosmos/src/lib.rs

@@ -1,6 +1,7 @@
 #![allow(clippy::enum_variant_names)]
 #![allow(clippy::new_without_default)]
 #![allow(clippy::module_inception)]
+#![cfg_attr(feature = "into_future", feature(into_future))]
 
 /*!
 # The Cosmos DB crate.

sdk/data_cosmos/src/operations/create_database.rs

@@ -64,7 +64,15 @@ impl CreateDatabaseBuilder {
     }
 }
 
-/// A future of a create database response
+#[cfg(feature = "into_future")]
+impl std::future::IntoFuture for CreateDatabaseBuilder {
+    type Future = CreateDatabase;
+    type Output = <CreateDatabase as std::future::Future>::Output;
+    fn into_future(self) -> Self::Future {
+        Self::into_future(self)
+    }
+}
+
 type CreateDatabase =
     futures::future::BoxFuture<'static, azure_core::error::Result<CreateDatabaseResponse>>;