update linting

changelog.d/6266.misc

@@ -0,0 +1 @@
+Add benchmarks for structured logging and improve output performance.

synapse/benchmarks/__main__.py

@@ -17,7 +17,6 @@ import pyperf
 
 from twisted.python import reflect
 
-from synapse.benchmarks import setupdb
 from synapse.benchmarks.suites import SUITES
 
 if __name__ == "__main__":

synapse/benchmarks/suites/logging.py

@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import sys
 import warnings
 from contextlib import redirect_stderr
 from io import StringIO
@@ -29,7 +28,6 @@ from twisted.logger import (
     Logger,
     LogPublisher,
     globalLogBeginner,
-    textFileLogObserver,
 )
 from twisted.protocols.basic import LineOnlyReceiver
 from twisted.python.failure import Failure