Off-by-two in pipeline-async parallelism

Description

The actual parallelism of pipeline-async is greater by 2 than what was passed. Here's the simplest reproduction case I could come up with:

Results in something like this:

Environment

[org.clojure/clojure "1.8.0"]
[org.clojure/core.async "0.2.374"]

Assignee

Unassigned

Reporter

import

Labels

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Approval

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Patch

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Priority

Minor
Configure