HistoryResponse iterator should be able to be traversed multiple times

[bmario]

The following code should work:

c = HistoryClient(...)
await c.connect()
response = await c.history_raw_timeline(...)
data = [(timestamp, value) for timestamp, value in response]
assert len(data) > 0
data = [(timestamp, value) for timestamp, value in response]
assert len(data) > 0 # this fails :(

This makes MetricQ hard to use in jupyter notebooks