node api becomes unresponsive while the node zips chain_data

[bladedoyle]

Problem:
The node becomes unresponsive during "grin_util::zip - compress" of chain data. The api does not respond while that zip is running.

Testcase:
Query the api at regular intervals (10 seconds) and display errors for API timeouts. The loop should print timestamps and indicate when there is a read timeout.
Wait and watch the nodes logs until there is a chain_data zip event. ex:
20201213 17:27:08.412 INFO grin_util::zip - compress: "/home/ubuntu/.grin/main/chain_data/txhashset_zip_000064e2beb9/kernel/pmmr_data.bin" -> "kernel/pmmr_data.bin"

Expected Result:
There should not be any api timeouts while the compress is running.

Actual Result:
The api times out
Error: HTTPConnectionPool(host='127.0.0.1', port=3413): Read timed out. (read timeout=20)