Credential for authentication.
str or :class:~azure.core.credentials.AzureKeyCredential
is treated as an API key.~azure.core.credentials.TokenCredential (e.g.
:class:~azure.identity.DefaultAzureCredential) is used with
azure_ad_token_provider.~azure.core.credentials_async.AsyncTokenCredential (e.g.
:class:~azure.identity.aio.DefaultAzureCredential) is used with
azure_ad_token_provider for asynchronous operations.None (default) falls back to
:class:~azure.identity.DefaultAzureCredential when
project_endpoint is used, or raises an error otherwise.