Have seperate variable on ap_writev to set the number of iovecs passed in and pass back the number of bytes written. Use ap_iovec_t on the call rather than struct iovec (I may reverse this tomorrow :-). Whatever we do, the network_io and file_io calls need to use iovecs consistently, which isn't the case now.
httpd/httpd/trunk/modules/mappers/mod_rewrite.c