refactor: Refactor client code to support multi-transport interactions and simplify client interfaces

.github/actions/spelling/allow.txt

@@ -71,5 +71,6 @@ sse
 tagwords
 taskupdate
 testuuid
+Tful
 typeerror
 vulnz

src/a2a/client/__init__.py

@@ -5,30 +5,67 @@
     CredentialService,
     InMemoryContextCredentialStore,
 )
-from a2a.client.client import A2ACardResolver, A2AClient
 from a2a.client.errors import (
     A2AClientError,
     A2AClientHTTPError,
     A2AClientJSONError,
     A2AClientTimeoutError,
 )
-from a2a.client.grpc_client import A2AGrpcClient
+from a2a.client.jsonrpc_client import (
+    JsonRpcClient,
+    JsonRpcTransportClient,
+    NewJsonRpcClient,
+)
+from a2a.client.grpc_client import (
+    GrpcTransportClient,
+    GrpcClient,
+    NewGrpcClient,
+)
 from a2a.client.helpers import create_text_message_object
 from a2a.client.middleware import ClientCallContext, ClientCallInterceptor
+from a2a.client.client import (
+    A2ACardResolver,
+    Client,
+    ClientConfig,
+    Consumer,
+    ClientEvent,
+)
+from a2a.client.client_factory import (
+    ClientFactory,
+    ClientProducer,
+    minimal_agent_card
+)
 
+# For backward compatability define this alias. This will be deprecated in
+# a future release.
+A2AClient = JsonRpcTransportClient
+A2AGrpcClient = GrpcTransportClient
 
 __all__ = [
     'A2ACardResolver',
-    'A2AClient',
     'A2AClientError',
     'A2AClientHTTPError',
     'A2AClientJSONError',
     'A2AClientTimeoutError',
-    'A2AGrpcClient',
     'AuthInterceptor',
     'ClientCallContext',
     'ClientCallInterceptor',
+    'Consumer',
     'CredentialService',
     'InMemoryContextCredentialStore',
     'create_text_message_object',
+    'A2AClient',  # for backward compatability
+    'A2AGrpcClient', # for backward compatability
+    'Client',
+    'ClientEvent',
+    'ClientFactory',
+    'ClientConfig',
+    'ClientProducer',
+    'GrpcTransportClient',
+    'GrpcClient',
+    'NewGrpcClient',
+    'JsonRpcClient',
+    'JsonRpcTransportClient',
+    'NewJsonRpcClient',
+    'minimal_agent_card',
 ]