How do I publish Boost unit tests with Jenkins pipeline and xUnit plugin

The answer turned out to be BoostTestJunitHudsonTestType. This is the code:

step([$class: 'XUnitBuilder',
            thresholds: [[$class: 'FailedThreshold', unstableThreshold: '1']],
            tools: [[$class: 'JUnitType', pattern: '**/surefire-reports/*.xml'],
                    [$class: 'JUnitType', pattern: '**/generatedJUnitFiles/JUnit/*.xml'],
                    [$class: 'BoostTestJunitHudsonTestType', pattern: '**/*_results.xml'],
                     ]])

The new xunit Plugin syntax is a bit lighter and more readable:

pipeline {
    agent any
    stages {
        stage('Test'){
            steps {
                sh "run_tests.bash"
            }
        }
    }
    post {
        always{
            xunit (
                thresholds: [ skipped(failureThreshold: '0'), failed(failureThreshold: '0') ],
                tools: [
                    JUnit(pattern: '**/surefire-reports/*.xml'),
                    JUnit(pattern: '**/generatedJUnitFiles/JUnit/*.xml'),
                    BoostTest(pattern: '**/*_results.xml')]
            )
        }
    }
 }

There's a class BoostTest in Jenkins' xUnit Plugin.