Function UnsafeAppend

cpp/src/arrow/buffer_builder.h:142–145

Unsafe methods don't check existing size

  // Unsafe methods don't check existing size
  void UnsafeAppend(const void* data, const int64_t length) {
    memcpy(data_ + size_, data, static_cast<size_t>(length));
    size_ += length;
  }

  void UnsafeAppend(std::string_view v) {
    UnsafeAppend(v.data(), static_cast<int64_t>(v.size()));