contentLength property
      
      int?
      get
      contentLength
      
    
    
The size of the request body, in bytes.
This defaults to null, which indicates that the size of the request is
not known in advance. May not be assigned a negative value.
Implementation
int? get contentLength => _contentLength;
      
      set
      contentLength
      (int? value) 
      
    
    
    
Implementation
set contentLength(int? value) {
  if (value != null && value < 0) {
    throw ArgumentError('Invalid content length $value.');
  }
  _checkFinalized();
  _contentLength = value;
}