The raw calls

The SDK ships a set of low-level functions under lk.raw. They are ordinary functions your plugin calls like any other, from the same import you already have, and they are what the rest of the SDK is built on: HTTP, UDP, websockets, storage, timers, the store. You reach for one when nothing on the declared surface does the job, and using one gives nothing else up: your inputs, your draw function and your connections keep working as before.

Most raw calls are requests, and the answer arrives in your onEvent function; Handling events is that side of the story. Each call returns -1 when your manifest did not ask for the capability it needs.

Family	Calls
Storage	storageGet, storagePut
HTTP	httpGet, httpFetch, HttpRequest, HttpResponse.header(name)
UDP	udpOpen, udpSend, udpClose
WebSocket	wsConnect(url, protocols), wsSend, wsClose
TCP	tcpConnect, tcpSend, tcpClose
Timers	timerSet(ms, repeat), timerCancel(id)
Files	fileRead, fileWrite, and the file_opened event
The store, raw	subscribePaths, aisSubscribe, pathValues(payload), targets(payload)
Publishing, raw	Publish and AisUpsert with a caller buffer and an explicit timestamp
The overlay, raw	Overlay: symbol, polyline, polygon, del, send, and the ownship-anchored and pick variants
Text	logf, status, raiseAlert, Buf, and the JSON helpers

The answers are typed payloads: TcpData, UdpData, WsOpen, WsData, WsClosed, HttpResponse, and FileOpened, whose writable field says whether fileWrite will be honoured.

The doc comments in plugins/common/lk.zig are the reference for each call, and event kinds is the wire reference for what each payload carries and when it arrives.