code: func NewClientContext(cred *sspi.Credentials, targetName string) (cc *ClientContext, outputToken []byte, err error) {
  	return NewClientContextWithFlags(cred, targetName, sspi.ISC_REQ_CONNECTION)
  }
docs: // NewClientContext creates a new client context. It uses client
  // credentials cred generated by AcquireCurrentUserCredentials or
  // AcquireUserCredentials and SPN to start a client Negotiate
  // negotiation sequence. targetName is the service principal name
  // (SPN) or the security context of the destination server.
  // NewClientContext returns a new token to be sent to the server.