Allocate a new filtering bufferevent on top of an existing bufferevent.
@param underlying the underlying bufferevent.
@param input_filter The filter to apply to data we read from the underlying
bufferevent
@param output_filter The filer to apply to data we write to the underlying
bufferevent
@param options A bitfield of bufferevent options.
@param free_context A function to use to free the filter context when
this bufferevent is freed.
@param ctx A context pointer to pass to the filter functions.
Allocate a new filtering bufferevent on top of an existing bufferevent.
@param underlying the underlying bufferevent. @param input_filter The filter to apply to data we read from the underlying bufferevent @param output_filter The filer to apply to data we write to the underlying bufferevent @param options A bitfield of bufferevent options. @param free_context A function to use to free the filter context when this bufferevent is freed. @param ctx A context pointer to pass to the filter functions.