convert all log_error_write() to log_error() and pass (log_error_st *)
use con->errh in preference to srv->errh (even though currently same)
avoid passing (server *) when previously used only for logging (errh)
code reuse, simplification, and inlining
remove excess calls to chunkqueue_remove_finished_chunks()
(it may still be possible for there to be an empty chunk in chunkqueue
if nothing were written to a temporary file (need to verify this), so
preserve some calls to chunkqueue_remove_finished_chunks() for now)
reduce initial buffer size if large POST to backend stored in temp files
regression in lighttpd 1.4.52
"[regression] lighttpd gets killed after uploading a big file"
quickly clear buffer instead of buffer_string_set_length(b, 0) or
buffer_reset(b). Avoids free() of large buffers about to be reused,
or buffers that are module-scoped, persistent, and reused.
(buffer_reset() should still be used with buffers in connection *con
when the data in the buffers is supplied by external, untrusted source)
server.chunkqueue-chunk-sz = 4096 (default)
Can be configured any integral value greater than 0.
Value is rounded up to next 1024 if not an even multiple of 1k.
Sites with large request or response headers may benefit from
an 8k or 16k chunk size. Embedded systems might choose to minimize
memory use by using a 1k chunk size.