For long string buffers, we currently write a null terminator one byte
past the end of the buffer. This can be seen with a record of the type
```
record(aai, foo) {
field(NELM, 1)
field(FTVL, CHAR)
field(INP, {const: "foo"})
}
```
where the buffer is only of size 1, but then we write at index 1 (aka
past the end of the buffer).
Co-authored-by: Lucas A. M. Magalhães <lucmaga@gmail.com>