DefaultChainCredentialsProvider   
  constructor(profileName: String? = null, platformProvider: PlatformProvider = PlatformProvider.System, httpClient: HttpClientEngine? = null, region: String? = null)
Parameters
profileName 
Override the profile name to use. If not provided it will be resolved internally via environment (see AwsSdkSetting.AwsProfile) or defaulted to default if not configured.
platformProvider 
The platform API provider
httpClient 
the HttpClientEngine instance to use to make requests. NOTE: This engine's resources and lifetime are NOT managed by the provider. Caller is responsible for closing.
region
the region to make credentials requests to.