NewClient returns a new `Client` instance which is used for signing and executing requests to AWS Lambda Function URLs, configured by 'uri' which is expected to take the form of: functionurl://?credentials={CREDENTIALS}&region={AWS_REGION} Where {CREDENTIALS} is a valid aaronland/go-aws-session credentials strings as described in https://github.com/aaronland/go-aws-session#credentials.

Client is a struct that implements methods for signing and executing requests to AWS Lambda Function URLs.