Static cache takes up too much memory

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- [x] Issue with the OpenXml library
- [ ] Question on library usage

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**Description**

I capture my application by dot Memory tool. And I find the OpenXML SDK take up too many memories to cache.


My application will use the OpenXML SDK to read the file once, and it means that the cache in SDK is wasteful

**Information**

- .NET Target: ALL
- DocumentFormat.OpenXml Version: 2.13.0

**Repro**

Not special

**Observed**

The OpenXML SDK take up too many memories to cache.

**Expected**

We can free it manual.

The report names no source file, test, or concrete reproduction beyond using OpenXML SDK 2.13.0 with a memory profiler. Start by reproducing the static-cache growth with the reported single-read scenario and trace the cache ownership in the SDK. Done means identifying the retained cache and providing a supported way to release it manually without breaking subsequent SDK use.

Written by the indexing model from the issue text.