Passing int64 losses precision sometimes.

[jmchn]

Proto file(s)
message UUID {
int64 most_significant_bits = 1;
int64 least_significant_bits = 2;
}

Command line arguments / config
ghz --proto .\some.proto --call some.service.method --insecure -d "uuid": {"most_significant_bits": -1472264933949945808, "least_significant_bits": -5032223331569284245}}}}}}" --rps 100 --connections 20 --concurrency 50 -m " --debug debug.out localhost:xxxx

Describe the bug
Just in case someone might have the same issue as I do, if you are use ghz for pressure testing a grpc service whose request has int64 variable in it, you might lose precision when passing in. I tested some smaller numbers and it was fine. I debugged into it and it seems that the json.Unmarshal([]byte(*data), &dataObj) caused it.

To Reproduce
As the setup above.

Expected behavior
Something like this should have been passed to the server.
{"uuid": {"most_significant_bits": -1472264933949945808, "least_significant_bits": -5032223331569284245}

Actual behavior
{"uuid":{"least_significant_bits":-5032223331569284000,"most_significant_bits":-1472264933949945900}
(the bits are weirdly truncated)

Environment

• OS: Win10 powershell & wsl.
• ghz: 0.120.0