Specifies maximum number of threads that object cache can serve concurrently. Each thread has its own memory pool. 

UnMarkThread must be called before a thread ends. Creating more threads than ThreadDimension will route additoinal threads in to the main threads pool. 

Before changing ThreadDimension the object cache may not be used: There may not be any TVec/TVecInt/TMtx/TMtxInt objects for which FreeIt was not called.

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