src/http/ngx_http_spdy_filter_module.c, latest changesets compiler warnings

In ngx_http_spdy_send_chain(ngx_connection_t *fc, ngx_chain_t *in, off_t limit):

src/http/ngx_http_spdy_filter_module.c(682) : warning C4244: 'function' : conversion from 'off_t' to 'size_t', possible loss of data

src/http/ngx_http_spdy_filter_module.c(701) : warning C4244: '-=' : conversion from 'off_t' to 'size_t', possible loss of data

src/http/ngx_http_spdy_filter_module.c(715) : warning C4244: 'function' : conversion from 'off_t' to 'size_t', possible loss of data

src/http/ngx_http_spdy_filter_module.c(751) : warning C4244: '=' : conversion from 'off_t' to 'size_t', possible loss of data

src/http/ngx_http_spdy_filter_module.c(757) : warning C4244: 'function' : conversion from 'off_t' to 'size_t', possible loss of data