added multithreaded tests, exeception handling tests

Signed-off-by: Sai Shree Pradhan <saishree.pradhan@databricks.com>

Author: saishreeeee

src/databricks/sql/telemetry/telemetry_client.py

@@ -149,6 +149,7 @@ class TelemetryClient(BaseTelemetryClient):
     # Telemetry endpoint paths
     TELEMETRY_AUTHENTICATED_PATH = "/telemetry-ext"
     TELEMETRY_UNAUTHENTICATED_PATH = "/telemetry-unauth"
+    DEFAULT_BATCH_SIZE = 10
 
     def __init__(
         self,
@@ -160,7 +161,7 @@ def __init__(
     ):
         logger.debug("Initializing TelemetryClient for connection: %s", session_id_hex)
         self._telemetry_enabled = telemetry_enabled
-        self._batch_size = 10  # TODO: Decide on batch size
+        self._batch_size = self.DEFAULT_BATCH_SIZE  # TODO: Decide on batch size
         self._session_id_hex = session_id_hex
         self._auth_provider = auth_provider
         self._user_agent = None
@@ -431,6 +432,9 @@ def close(session_id_hex):
                 logger.debug(
                     "No more telemetry clients, shutting down thread pool executor"
                 )
-                TelemetryClientFactory._executor.shutdown(wait=True)
+                try:
+                    TelemetryClientFactory._executor.shutdown(wait=True)
+                except Exception as e:
+                    logger.debug("Failed to shutdown thread pool executor: %s", e)
                 TelemetryClientFactory._executor = None
                 TelemetryClientFactory._initialized = False