fix: Stop using api_core default timeouts in publish since they are

broken

google/cloud/pubsub_v1/types.py

@@ -35,6 +35,7 @@
 from google.protobuf import timestamp_pb2
 
 from google.api_core.protobuf_helpers import get_messages
+from google.api_core.timeout import ExponentialTimeout
 
 from google.pubsub_v1.types import pubsub as pubsub_gapic_types
 
@@ -191,7 +192,12 @@ class PublisherOptions(NamedTuple):
         "an instance of :class:`google.api_core.retry.Retry`."
     )
 
-    timeout: "OptionalTimeout" = gapic_v1.method.DEFAULT  # use api_core default
+    # Use ExponentialTimeout instead of api_core default because the default
+    # value results in retries with zero deadline.
+    # Refer https://github.com/googleapis/python-api-core/issues/654
+    timeout: "OptionalTimeout" = ExponentialTimeout(
+        initial=5, maximum=60, multiplier=1.3, deadline=600
+    )
     (
         "Timeout settings for message publishing by the client. It should be "
         "compatible with :class:`~.pubsub_v1.types.TimeoutType`."