Properties of a PullMessage.
Properties:
| Name | Type | Attributes | Description | 
|---|---|---|---|
payload | 
      
      Uint8Array | null | 
            
              <optional> | 
        
        
        
           PullMessage payload  | 
    
tag | 
      
      string | null | 
            
              <optional> | 
        
        
        
           PullMessage tag  |