func NewFromEnv() *EC2Manager {
	c := tcclient.CredentialsFromEnvVars()
	return &EC2Manager{
		Credentials:  c,
		BaseURL:      DefaultBaseURL,
		Authenticate: c.ClientID != "",
	}
}
func NewFromEnv() *EC2Manager {
	c := tcclient.CredentialsFromEnvVars()
	return &EC2Manager{
		Credentials:  c,
		BaseURL:      DefaultBaseURL,
		Authenticate: c.ClientID != "",
	}
}
// NewFromEnv returns an EC2Manager client with credentials taken from the environment variables:
//
//  TASKCLUSTER_CLIENT_ID
//  TASKCLUSTER_ACCESS_TOKEN
//  TASKCLUSTER_CERTIFICATE
//
// If environment variables TASKCLUSTER_CLIENT_ID is empty string or undefined
// authentication will be disabled.