Optimize CGrpcServer getters (#1284)

* Add ResultInfo._description in result_info.py

* Bypass location in available results when LegacyGrpc as it is too slow

* Tests on ResultInfo.__str__ skip LegacyGrpc

* Cache call to result_info_grpcapi.py list_result

* Cache call to result_info_grpcapi.py result_info_get_int_property

* Cache call to result_info_grpcapi.py result_info_get_string_property

* Cache call to result_info_grpcapi.py list

* Revert "Tests on ResultInfo.__str__ skip LegacyGrpc"

This reverts commit ff45b25.

* Revert "Bypass location in available results when LegacyGrpc as it is too slow"

This reverts commit e9a2888.

* Remove unreachable code

* Cache GrpcServer.version and GrpcServer.os

* Remove useless import

* Remove changes to gate code

src/ansys/dpf/core/result_info.py

@@ -144,9 +144,12 @@ def __str__(self):
             return txt
         except Exception as e:
             raise e
-            from ansys.dpf.core.core import _description
 
-            return _description(self._internal_obj, self._server)
+    @property
+    def _description(self):
+        from ansys.dpf.core.core import _description
+
+        return _description(self._internal_obj, self._server)
 
     @property
     def _names(self):

src/ansys/dpf/core/server_types.py

@@ -678,6 +678,8 @@ def __init__(
         self._grpc_client_path = load_api.load_grpc_client(ansys_path=ansys_path)
         self._own_process = launch_server
         self._local_server = False
+        self._os = None
+        self._version = None
 
         address = f"{ip}:{port}"
 
@@ -735,21 +737,24 @@ def _check_first_call(self, num_connection_tryouts):
 
     @property
     def version(self):
-        from ansys.dpf.gate import data_processing_capi, integral_types
+        if not self._version:
+            from ansys.dpf.gate import data_processing_capi, integral_types
 
-        api = data_processing_capi.DataProcessingCAPI
-        major = integral_types.MutableInt32()
-        minor = integral_types.MutableInt32()
-        api.data_processing_get_server_version_on_client(self.client, major, minor)
-        out = str(int(major)) + "." + str(int(minor))
-        return out
+            api = data_processing_capi.DataProcessingCAPI
+            major = integral_types.MutableInt32()
+            minor = integral_types.MutableInt32()
+            api.data_processing_get_server_version_on_client(self.client, major, minor)
+            self._version = str(int(major)) + "." + str(int(minor))
+        return self._version
 
     @property
     def os(self):
-        from ansys.dpf.gate import data_processing_capi
+        if not self._os:
+            from ansys.dpf.gate import data_processing_capi
 
-        api = data_processing_capi.DataProcessingCAPI
-        return api.data_processing_get_os_on_client(self.client)
+            api = data_processing_capi.DataProcessingCAPI
+            self._os = api.data_processing_get_os_on_client(self.client)
+        return self._os
 
     def _create_shutdown_funcs(self):
         from ansys.dpf.gate import data_processing_capi