Many tests failed at the same time in this package.

• I will close this issue when there are no more failures in this package and
  there is at least one pass.
• No new issues will be filed for this package until this issue is closed.
• If there are already issues for individual test cases, I will close them when
  the corresponding test passes. You can close them earlier, if you prefer, and
  I won't reopen them while this issue is still open.

Here are the tests that failed:

• test_streaming_pull_callback_error_propagation[grpc-grpc] (tests.system.TestStreamingPull: test_streaming_pull_callback_error_propagation[grpc-grpc] failed #1521)
• test_streaming_pull_callback_error_propagation[grpc-rest] (tests.system.TestStreamingPull: test_streaming_pull_callback_error_propagation[grpc-rest] failed #1446)
• test_streaming_pull_callback_error_propagation[rest-grpc] (tests.system.TestStreamingPull: test_streaming_pull_callback_error_propagation[rest-grpc] failed #1529)
• test_streaming_pull_callback_error_propagation[rest-rest] (tests.system.TestStreamingPull: test_streaming_pull_callback_error_propagation[rest-rest] failed #1518)
• test_streaming_pull_ack_deadline[grpc-grpc] (tests.system.TestStreamingPull: test_streaming_pull_ack_deadline[grpc-grpc] failed #1441)
• test_streaming_pull_ack_deadline[grpc-rest]
• test_streaming_pull_ack_deadline[rest-grpc] (tests.system.TestStreamingPull: test_streaming_pull_ack_deadline[rest-grpc] failed #1519)
• test_streaming_pull_ack_deadline[rest-rest]
• test_streaming_pull_max_messages[grpc-grpc] (tests.system.TestStreamingPull: test_streaming_pull_max_messages[grpc-grpc] failed #1522)
• test_streaming_pull_max_messages[grpc-rest] (tests.system.TestStreamingPull: test_streaming_pull_max_messages[grpc-rest] failed #1523)
• test_streaming_pull_max_messages[rest-grpc] (tests.system.TestStreamingPull: test_streaming_pull_max_messages[rest-grpc] failed #1524)
• test_streaming_pull_max_messages[rest-rest] (tests.system.TestStreamingPull: test_streaming_pull_max_messages[rest-rest] failed #1525)
• test_streaming_pull_blocking_shutdown[grpc-grpc] (tests.system.TestStreamingPull: test_streaming_pull_blocking_shutdown[grpc-grpc] failed #1530)
• test_streaming_pull_blocking_shutdown[grpc-rest] (tests.system.TestStreamingPull: test_streaming_pull_blocking_shutdown[grpc-rest] failed #1449)
• test_streaming_pull_blocking_shutdown[rest-grpc] (tests.system.TestStreamingPull: test_streaming_pull_blocking_shutdown[rest-grpc] failed #1531)
• test_streaming_pull_blocking_shutdown[rest-rest] (tests.system.TestStreamingPull: test_streaming_pull_blocking_shutdown[rest-rest] failed #1532)

commit: 171f7d4
buildURL: Build Status, Sponge
status: failed