typedef struct SilcAsyncOperationObject SilcAsyncOperationStruct;

    The asynchronous operation context that can be used as a pre-allocated
    context.  This is initialized with silc_async_init.  It need not
    be uninitialized.  The layer that implements the asynchronous
    operation initializes this context.  The layer that has access to this
    context can use it to control the underlaying asynchronous operation.