String Merge(Allocator allocator, Array<String> list, String separator = " ") {
    int64_t char_count = 0;
    For(list) char_count += it.len;
    if (char_count == 0) return {};
    int64_t node_count = list.len;

    int64_t base_size = (char_count + 1);
    int64_t sep_size  = (node_count - 1) * separator.len;
    int64_t size      = base_size + sep_size;
    char   *buff      = (char *)AllocSize(allocator, sizeof(char) * (size + 1));
    String  string    = {buff, 0};
    For(list) {
        Assert(string.len + it.len <= size);
        memcpy(string.data + string.len, it.data, it.len);
        string.len += it.len;
        if (!list.is_last(it)) {
            memcpy(string.data + string.len, separator.data, separator.len);
            string.len += separator.len;
        }
    }
    Assert(string.len == size - 1);
    string.data[size] = 0;
    return string;
}