[C++] Use atomic backpressure counter

[asfimport]

There are a few places in the code (sink_node.cc, source_node.cc, file_base.cc) where the backpressure counter is of type int32_t. This prevents ExecNode::Pause(...) and  ExecNode::Resume(...) from being thread-safe. The proposal is to make these backpressure counters be of type std::atomic<int32_t>.

Reporter: Yaron Gvili / @rtpsw
Assignee: Yaron Gvili / @rtpsw

PRs and other links:

• GitHub Pull Request #14622

_{Note: This issue was originally created as ARROW-18310. Please see the migration documentation for further details.}

[asfimport]

Weston Pace / @westonpace:
Issue resolved by pull request 14622
#14622