dev: use from_reader and to_writer_pretty from serde_json, remove reading from memory to string
#156
| Job | Run time |
|---|---|
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| 8m 49s | |
| 22s | |
| 10s | |
| 51s | |
| 4m 49s | |
| 4m 9s | |
| 22m 43s |