Merge v0.2 branch back to master for PR #273 (#400)

* fix bugs due to ts.tailstream (#273)

src/sdk/pynni/nni/platform/local.py

@@ -22,6 +22,7 @@ import os
 import json
 import time
 import json_tricks
+import subprocess
 
 from ..common import init_logger, env_args
 
@@ -77,6 +78,7 @@ def send_metric(string):
     assert len(data) < 1000000, 'Metric too long'
     _metric_file.write(b'ME%06d%b' % (len(data), data))
     _metric_file.flush()
+    subprocess.run(['touch', _metric_file.name], check = True)
 
 def get_sequence_id():
     return os.environ['NNI_TRIAL_SEQ_ID']
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