Make FluxTable and FluxRecord json serializable

[russorat]

it would be really handy for debugging if the objects returned from the write_api were json serializable by default (FluxTable and FluxRecord). this would avoid the need to do stuff like json.dumps(record.__dict__)

I think for this you would simply need to supply a toJSON function in those classes.

[bednar]

@russorat thanks for suggestion to enhancement, I will take a look.

[bednar]

@russorat, unfortunately the toJSON is not enough. Because json.dumps needs to have defined a default parameter that returns a serializable object.

I have prepared a FluxStructureEncoder encoder which simplifies usage of json encoder to:

import json
from influxdb_client.client.flux_table import FluxStructureEncoder

output = json.dumps(tables, cls=FluxStructureEncoder, indent=2)
print(output)