in src/rosbridge/timeseq.py [0:0]
def open_chunk(self, channel_name, chunk):
fn = path.join(self.trace_dir, 'chunk_%s_%d.json.gz' % (channel_name, int(chunk)))
f = gzip.open(fn, 'wb')
self.files_by_channel[channel_name] = f
self.chunks_by_channel[channel_name] = chunk
self.times_by_channel[channel_name] = []
f.write('{"samples":[')