Representation of a content type. An instance of ContentType is immutable.

abstract class ContentType implements HeaderValue {
 /**
  * Creates a new content type object setting the primary type and
  * sub type. The charset and additional parameters can also be set
  * using [charset] and [parameters]. If charset is passed and
  * [parameters] contains charset as well the passed [charset] will
  * override the value in parameters. Keys and values passed in
  * parameters will be converted to lower case.
  */
 factory ContentType(String primaryType,
                     String subType,
                     {String charset, Map<String, String> parameters}) {
   return new _ContentType(primaryType, subType, charset, parameters);
 }

 /**
  * Creates a new content type object from parsing a Content-Type
  * header value. As primary type, sub type and parameter names and
  * values are not case sensitive all these values will be converted
  * to lower case. Parsing this string
  *
  *     text/html; charset=utf-8
  *
  * will create a content type object with primary type [:text:], sub
  * type [:html:] and parameter [:charset:] with value [:utf-8:].
  */
 static ContentType parse(String value) {
   return _ContentType.parse(value);
 }

 /**
  * Gets the mime-type, without any parameters.
  */
 String get mimeType;

 /**
  * Gets the primary type.
  */
 String get primaryType;

 /**
  * Gets the sub type.
  */
 String get subType;

 /**
  * Gets the character set.
  */
 String get charset;
}