Bedrock API key.
Enables authentication using Bedrock API keys instead of standard AWS
credentials. When provided, the key is set as the AWS_BEARER_TOKEN_BEDROCK
environment variable.
.. warning::
Because this sets a process-wide environment variable, using
api_key is not compatible with multi-tenant deployments where
different model instances in the same process need different API keys.
Each new client creation overwrites the previous value. Use standard
AWS credentials (IAM roles, profiles, etc.) for multi-tenant scenarios.
See: https://docs.aws.amazon.com/bedrock/latest/userguide/api-keys-use.html
If not provided, will be read from AWS_BEARER_TOKEN_BEDROCK environment
variable (if it exists).
If both an API key and AWS credentials are present, the API key takes precedence.
