Replace io.ReadAll(resp.Body) on the typed Call/callMultipart paths with a sync.Pool-backed bytes.Buffer + ReadFrom. Saves the 512B initial allocation that ReadAll grows from on every successful call.
The pool only covers paths whose decoder copies strings out of the input (decodeResult delegates to goccy/go-json, which copies). CallRaw and callMultipartRaw return slices that alias the buffer storage, so they keep the io.ReadAll path; pooling there would need a defensive copy that defeats the saving.
putRespBuf caps Cap() at 64 KiB before returning to the pool so a single oversized response (e.g. large getFile metadata) doesn't bloat the pool for the rest of the process.
Bench delta on Call_BoolResponse: 14 allocs -> 13 allocs, 1842B -> 1331B, 526ns -> 479ns. Same shape on Call_StructResponse (16 -> 15, 1973B -> 1462B).
