Write constructor
      
      Write({ 
    
    
- Precondition? currentDocument,
- String? delete,
- DocumentTransform? transform,
- Document? update,
- DocumentMask? updateMask,
- List<FieldTransform> ? updateTransforms,
Implementation
Write({
  this.currentDocument,
  this.delete,
  this.transform,
  this.update,
  this.updateMask,
  this.updateTransforms,
});