diff --git a/include/fluent-bit/flb_connection.h b/include/fluent-bit/flb_connection.h
index 53f28b974e4..31801e71e09 100644
--- a/include/fluent-bit/flb_connection.h
+++ b/include/fluent-bit/flb_connection.h
@@ -58,12 +58,26 @@ struct flb_net_setup;
 struct flb_upstream;
 struct flb_downstream;
 struct flb_tls_session;
+struct flb_connection;
+
+typedef void (*flb_connection_drop_notification_callback)(
+                 struct flb_connection *connection);
 
 /* Base network connection */
 struct flb_connection {
     struct mk_event event;
 
     void *user_data;
+    /*
+     * Optional notification invoked from prepare_destroy_conn() while the
+     * connection is still linked on busy_queue and before the event is
+     * deregistered and the file descriptor is closed.
+     *
+     * Callers may detach external state here, but must not free, destroy or
+     * unlink the connection because prepare_destroy_conn() performs the final
+     * teardown immediately after the callback returns.
+     */
+    flb_connection_drop_notification_callback drop_notification_callback;
 
     /* Socket */
     flb_sockfd_t fd;
diff --git a/src/flb_connection.c b/src/flb_connection.c
index a3ed402651b..34b1cc229c7 100644
--- a/src/flb_connection.c
+++ b/src/flb_connection.c
@@ -254,4 +254,4 @@ void flb_connection_unset_io_timeout(struct flb_connection *connection)
     assert(connection != NULL);
 
     connection->ts_io_timeout = -1;
-}
\ No newline at end of file
+}
diff --git a/src/flb_downstream.c b/src/flb_downstream.c
index 34c37d0851d..1de1376cd26 100644
--- a/src/flb_downstream.c
+++ b/src/flb_downstream.c
@@ -209,6 +209,10 @@ static int prepare_destroy_conn(struct flb_connection *connection)
     flb_trace("[downstream] destroy connection #%i to %s",
               connection->fd, flb_connection_get_remote_address(connection));
 
+    if (connection->drop_notification_callback != NULL) {
+        connection->drop_notification_callback(connection);
+    }
+
     if (MK_EVENT_IS_REGISTERED((&connection->event))) {
         mk_event_del(connection->evl, &connection->event);
     }