in src/signing.c [79:87]
void aws_crt_signing_config_aws_set_region(
aws_crt_signing_config_aws *signing_config,
const uint8_t *region,
size_t region_length) {
aws_byte_buf_clean_up(&signing_config->region);
struct aws_byte_buf input = aws_byte_buf_from_array(region, region_length);
aws_byte_buf_init_copy(&signing_config->region, aws_crt_default_allocator(), &input);
signing_config->config.region = aws_byte_cursor_from_buf(&signing_config->region);
}