Simdjson https://github.com/simdjson/simdjson requires a specified simdjson::SIMDJSON_PADDING bytes of padding at the end of the JSON data.

Is it safe to okay if non-null characters are in this padding area? Will this area be modified?

auto constexpr json_length = 3;
auto constexpr buffer_size = json_length + simdjson::SIMDJSON_PADDING; 
char buff[buffer_size] = { '[', '1', ']' }; //relevant json

for (size_t i = json_length; i < buffer_size; ++i) {
    buffer[i] = 'j'; 
} //does simdjson modify this part  of the buffer in the usage below or is it required to be unused/uninitialized?

simdjson::ondemand::parser parser;
parser.iterate(buff, json_length, buffer_size);