func NewChainCredentials(providers []Provider) *Credentials {
	return NewCredentials(&ChainProvider{
		Providers: append([]Provider{}, providers...),
	})
}
NewChainCredentials returns a pointer to a new Credentials object
wrapping a chain of providers.
package credentials
import (
	"github.com/aws/aws-sdk-go/aws/awserr"
)
var (
	ErrNoValidProvidersFoundInChain = awserr.New("NoCredentialProviders",
		`no valid providers in chain. Deprecated. 
	For verbose messaging see aws.Config.CredentialsChainVerboseErrors`,
		nil)
)
type ChainProvider struct {
	Providers     []Provider
	curr          Provider
	VerboseErrors bool
}