Share data loader to across asyncio boto sessions (#40658)

By default, a botocore session creates and caches an instance of JSONDecoder which
consumes a lot of memory.  This issue was reported here boto/botocore#3078.
In the context of triggers which use boto sessions, this can result in excessive
memory usage and as a result reduced capacity on the triggerer.  We can reduce
memory footprint by sharing the loader instance across the sessions.

airflow/providers/amazon/aws/hooks/base_aws.py

@@ -70,6 +70,19 @@
 
  from airflow.models.connection import Connection # Avoid circular imports.
 
+_loader = botocore.loaders.Loader()
+"""
+botocore data loader to be used with async sessions
+
+By default, a botocore session creates and caches an instance of JSONDecoder which
+consumes a lot of memory. This issue was reported here https://github.com/boto/botocore/issues/3078.
+In the context of triggers which use boto sessions, this can result in excessive
+memory usage and as a result reduced capacity on the triggerer. We can reduce
+memory footprint by sharing the loader instance across the sessions.
+
+:meta private:
+"""
+
 
 class BaseSessionFactory(LoggingMixin):
  """
@@ -155,7 +168,9 @@ def _apply_session_kwargs(self, session):
  def get_async_session(self):
  from aiobotocore.session import get_session as async_get_session
 
- return async_get_session()
+ session = async_get_session()
+ session.register_component("data_loader", _loader)
+ return session
 
  def create_session(
  self, deferrable: bool = False