libSceNet technical debt

PPSA01530, PPSA23827 and PPSA13356 imports declared without parameters, signatures unknown, added without an implementation because the titles fail to load without them: sceNetShowIfconfig (libSceNet), sce::Json::Value::setNullAccessCallBack (libSceJson2), kqueue and kevent (libkernel), and scePadUnknown_n3kSX62fgNo (libScePad), whose real name is unknown. _sceUltWaitingQueueResourcePoolCreate, _sceUltSemaphoreCreate, _sceUltMutexOptParamInitialize, _sceUltMutexCreate, _sceUltQueueDataResourcePoolCreate and _sceUltQueueCreate (libSceUlt) forward to the exports without the underscore; that their argument lists match is inferred from the other underscore Ult exports, not measured.
sceHttp2GetMemoryPoolStats, sceSslGetMemoryPoolStats, sceNetGetMemoryPoolStats (libSceHttp2, libSceSsl, libSceNet) - the signatures (int id, stats*), the layouts (pool size, peak and current use, and for Http2 and Ssl a 32-bit reserved field) and the error codes were measured on a PS5 (firmware 13.60). The pool size is the one given at init or pool creation; nothing is allocated from these pools, so the peak and current use are 0, where the console already reports use right after initialization (0x15C0 bytes for Ssl, 0x1640 for Http2 and 4 for a Net pool)
sceNetShowNetstat (libSceNet) - imported by PPSA11386 and not called during its start-up; unknown signature, declared without parameters

sceNetSetsockopt (libSceNet) sets SO_RCVTIMEO and SO_SNDTIMEO as the host socket's timeouts. On Windows a receive or send on a stream socket that times out fails with ETIMEDOUT, where FreeBSD returns EAGAIN or the partial count: Winsock leaves the connection in an indeterminate state after a timeout and reports no partial count (SOL_SOCKET options), so FreeBSD's behaviour needs the timeout waited for without the host option. A receive on a datagram socket that times out fails with EAGAIN
sceNetSendmsg and sceNetRecvmsg (libSceNet) copy the scatter/gather list through one host buffer and accept only the flags sceNetSend/sceNetRecv accept. Sending control data throws; a receive never returns control data (msg_controllen 0), since no socket option that queues it is supported