__ntapi_dsr_start_impl(): copy the loop routine addr and ctx onto the stack.
    
    Since params might point to an address on the stack of the thread which
    called __ntapi_dsr_init(), and given that __ntapi_dsr_init() returns as
    soon as the internal client connection had been established, we may not
    access params upon return from __ntapi_dsr_connect_internal_client().