Issue #12836 has been reported by Tomoyuki Chikanaga.

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Bug #12836: Backport r56416 (copy_stream to duplex IO)
https://bugs.ruby-lang.org/issues/12836

* Author: Tomoyuki Chikanaga
* Status: Closed
* Priority: Normal
* Assignee: 
* ruby -v: -
* Backport: 2.1: DONTNEED, 2.2: DONTNEED, 2.3: REQUIRED
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バックポート管理用チケットです。



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