public bool SupportExtensionObjects {get; set;}

'Declaration
 
Public Property SupportExtensionObjects As Boolean

Property Value

Note that custom Subscriber fields are not affected by this connection string parameter, they are always available in the same way as predefined Subscriber fields.

Reading data extension information can take additional time. If you don't need to work with data extensions, it's better to disable their reading by setting the SupportExtensionObjects connection string parameter to false.

Reference

ExactTargetConnectionStringBuilder Class
ExactTargetConnectionStringBuilder Members
Working with ExactTarget Custom Fields and Data Extensions