pub fn new() -> ChainProvider {
        ChainProvider {
            environment_provider: EnvironmentProvider::default(),
            profile_provider: ProfileProvider::new().ok(),
            instance_metadata_provider: InstanceMetadataProvider::new(),
            container_provider: ContainerProvider::new(),
        }
    }
Create a new `ChainProvider` using a `ProfileProvider` with the default settings.
rusoto/credential/src/lib.rs