object which should be passed during the initialization for DownstreamElectronFE#init.
It should implements 2 methods for creating and removing the persistent session
        
        
Members
PersistentConfig
    persistent config needed to be passed to Persistent#createPersistentSession
    Properties:
| Name | Type | Attributes | Description | 
|---|---|---|---|
licenseUrl | 
            
            string | url to license server | |
serverCertificate | 
            
            Uint8Array | server certificate | |
pssh | 
            
            string | 
                
                    <optional> | 
            
            
            protection information from manifest for widevine (ContentProtection), this is base64 string if not provided it will be injected automatically by API | 
licenseRequest | 
            
            object | 
                
                    <optional> | 
            
            
            The callback function that will be triggered before the request, for example when you need to add request headers | 
licenseResponse | 
            
            object | 
                
                    <optional> | 
            
            
            The callback function that will be triggered with the request | 
Example
var config = {
  licenseUrl: 'https://lic.staging.drmtoday.com/license-proxy-widevine/cenc/',
  serverCertificate: new Uint8Array(<server_certificate>),
  licenseRequest: function (request) {
    request.setRequestHeader('<headerParam>', '<headerValue>');
    .....
    request.setRequestHeader('Authorization', '........');
    request.setRequestHeader('dt-custom-data', '........');
  },
  licenseResponse: function (request) {
    console.log(request.getAllResponseHeaders());
  }
};
        
    
    
        Methods
createPersistentSession(config) → {Promise}
    should create a persistent session and resolve it with sessionId
    Parameters:
| Name | Type | Description | 
|---|---|---|
config | 
            
            Persistent#PersistentConfig | persistent config | 
Returns:
- Type
 - Promise
 
removePersistentSession(sessionId) → {Promise}
    remove persistent session
    Parameters:
| Name | Type | Description | 
|---|---|---|
sessionId | 
            
            string | session identifier | 
Returns:
- Type
 - Promise