feat: implement async rest mixin methods

gapic/templates/%namespace/%name_%version/%sub/services/%service/_shared_macros.j2

@@ -353,8 +353,6 @@ class {{ async_method_name_prefix }}{{ service.name }}RestInterceptor:
     {% endif %}{# if (not is_async) or (is_async and not method.lro and not method.extended_lro and not method.paged_result_field) #}
     {% endfor %}
 
-    {# TODO(https://github.com/googleapis/gapic-generator-python/issues/2148): Remove the condition below once mixins are supported for async rest transport. #}
-    {% if not is_async %}
     {% for name, signature in api.mixin_api_signatures.items() %}
     {{ async_prefix }}def pre_{{ name|snake_case }}(
         self, request: {{signature.request_type}}, metadata: Sequence[Tuple[str, str]]
@@ -377,7 +375,6 @@ class {{ async_method_name_prefix }}{{ service.name }}RestInterceptor:
         """
         return response
     {% endfor %}
-    {% endif %}
 {% endmacro %}
 
 {% macro generate_mixin_call_method(service, api, name, sig, is_async) %}

gapic/templates/%namespace/%name_%version/%sub/services/%service/async_client.py.j2

@@ -21,6 +21,7 @@ from google.api_core.client_options import ClientOptions
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest_asyncio.py.j2

@@ -225,6 +225,9 @@ class Async{{service.name}}RestTransport(_Base{{ service.name }}RestTransport):
         return self._{{method.name}}(self._session, self._host, self._interceptor)  # type: ignore
 
     {% endfor %}
+    {% for name, sig in api.mixin_api_signatures.items() %} 
+    {{ shared_macros.generate_mixin_call_method(service, api, name, sig, is_async=True) | indent(4) }}
+    {% endfor %}
 
     @property
     def kind(self) -> str:

gapic/templates/tests/unit/gapic/%name_%version/%sub/test_macros.j2

@@ -1884,11 +1884,8 @@ def test_unsupported_parameter_rest_asyncio():
 {% endfor %}{# for method in service.methods.values() #}
 {% for name, sig in api.mixin_api_signatures.items() %}
 {% if 'rest' in transport %}
-{# TODO: Remove the following condition as we implement async mixins #}
-{% if not is_async %}
 {{ bad_request_mixins_test(service, api, name, sig, transport, is_async) }}
 {{ call_success_mixins_test(service, api, name, sig, transport, is_async) }}
-{% endif %}{# if not is_async #}
 {% endif %}{# if 'rest' in transport #}
 {% endfor %}
 {{ initialize_client_with_transport_test(service, transport, is_async) }}

tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore
 

tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/async_client.py

@@ -23,6 +23,7 @@
 from google.api_core import exceptions as core_exceptions
 from google.api_core import gapic_v1
 from google.api_core import retry_async as retries
+import google.auth
 from google.auth import credentials as ga_credentials   # type: ignore
 from google.oauth2 import service_account              # type: ignore