: Update(asyncKeyword, parameter, arrowToken, null, (ExpressionSyntax)body);
: Update(asyncKeyword, delegateKeyword, parameterList, null, (ExpressionSyntax)body);
? Update(asyncKeyword, parameterList, arrowToken, block, null) : Update(asyncKeyword, parameterList, arrowToken, null, (ExpressionSyntax)body);
? Update(asyncKeyword, delegateKeyword, parameterList, block, null) : Update(