private void UpdateFileHeader(BinaryWriter writer, long offsetTableOffset)
{
writer.BaseStream.Position = 0x0;
writer.Write(0); // 0x0 uint32 unknown
writer.Write((uint)offsetTableOffset); // 0x4 uint32 offset table offset
writer.Write(_tags.Count); // 0x8 uint32 number of tags
writer.Write(0); // 0xC uint32 unknown
writer.Write(Timestamp); // 0x10 uint64 timestamp
writer.Write(0); // 0x18 uint32 unknown
writer.Write(0); // 0x1C uint32 unknown
}