How to set credentials for google speech to text without setting environment variable?

Question

Google

This is an example of using the client-libraries-usage-csharp c# library .
This is how the environment variable is set:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/[FILE_NAME].json"

How to set credentials for google speech to text without setting environment variable?
Something like this:
var credentials = ...create(file.json); var speech = SpeechClient.Create(credentials);