nitroAllocCString method
Copies s into a <lib>_nitro_alloc'd NUL-terminated buffer — for
values whose ownership transfers to native (e.g. callback string
returns, which the bridge frees with its own free).
Implementation
int nitroAllocCString(String s) {
final bytes = encodeCString(s);
final p = nitroAlloc(bytes.length);
writeBytes(p, bytes);
return p;
}