code: function checkUriEndpointState(key, value)
  {
    if(typeof value != 'string')
      throw SyntaxError(key+' param should be a String, not '+typeof value);
  
    if(!value.match('STOP|START|PAUSE'))
      throw SyntaxError(key+' param is not one of [STOP|START|PAUSE] ('+value+')');
  }
docs: State of the endpoint
  
  @typedef core/complexTypes.UriEndpointState
  
  @type {(STOP|START|PAUSE)}
   
  Checker for {@link module:core/complexTypes.UriEndpointState}
  
  @memberof module:core/complexTypes
  
  @param {external:String} key
  @param {module:core/complexTypes.UriEndpointState} value