code: function AzureAdapter (options, schema) {
  	this.options = assign({}, DEFAULT_OPTIONS, options.azure);
  
  	if (this.options.accountName || this.options.connectionString) {
  		this.blobSvc = azure.createBlobService(
  			this.options.accountName || this.options.connectionString,
  			this.options.accountKey,
  			this.options.host
  		);
  	} else {
  		// If no connection configuration is supplied, azure will pull it from
  		// environment variables.
  		this.blobSvc = azure.createBlobService();
  	}
  
  	// Verify that the container setting exists.
  	if (!this.options.container) {
  		throw Error('Azure storage configuration error: missing container setting');
  	}
  	this.container = this.options.container;
  
  	// Ensure the generateFilename option takes a callback
  	this.options.generateFilename = ensureCallback(this.options.generateFilename);
  }
docs: The schema can contain the additional fields { container, etag }. See README.md for details and usage examples.