code: func (c *Client) Valid() bool {
  	if c == nil {
  		return false
  	}
  
  	if c.Client == nil {
  		return false
  	}
  
  	// Use arbitrary pointer field in the service content.
  	// Doesn't matter which one, as long as it is populated by default.
  	if c.ServiceContent.SessionManager == nil {
  		return false
  	}
  
  	return true
  }
docs: // Valid returns whether or not the client is valid and ready for use.
  // This should be called after unmarshalling the client.