Hello,

Package v3.0.0 introducted the GetUserName function here: https://github.com/Azure/Microsoft.Azure.StackExchangeRedis/blob/main/src/AzureCacheOptions.cs#L81
Which is used to assign the User property on the ConfigurationOptions here: https://github.com/Azure/Microsoft.Azure.StackExchangeRedis/blob/main/src/AzureCacheForRedis.cs#L116

However, the function is not used to override the User property of the AzureOptionsProvider base class of AzureCacheOptionsProviderWithToken
which is assigned to ConfigurationOptions.Default here: https://github.com/Azure/Microsoft.Azure.StackExchangeRedis/blob/main/src/AzureCacheForRedis.cs#L115

As a consequence, when the reauthentication is done here: https://github.com/Azure/Microsoft.Azure.StackExchangeRedis/blob/main/src/AzureCacheOptionsProviderWithToken.cs#L241
The User property passed is null because not overridden (as it was in v2.0.0 of the package).

This makes the execution failed systematically, with error "ERR protocol error: invalid bulk length".

To solve this bug, you have to override the User property inside the AzureCacheOptionsProviderWithToken class, and assign its value from the GetUserName function of the AzureCacheOptions