Add async functions support

[lin-calvin]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions.
• If pull request breaks tests it would not be merged.

Description of the Change

Add the support of async functions

Benefits

Async functions are supported

Possible Drawbacks

User functions may throw errors when calling await response.async_json

Applicable Issues

#116