presto-main/src/main/java/io/prestosql/sql/analyzer/FeaturesConfig.java/FeaturesConfig/setConcurrentLifespansPerTask
class FeaturesConfig:    @Config("concurrent-lifespans-per-task")
    @ConfigDescription("Experimental: Default number of lifespans that run in parallel on each task when grouped execution is enabled")
    // When set to zero, a limit is not imposed on the number of lifespans that run in parallel
    public FeaturesConfig setConcurrentLifespansPerTask(int concurrentLifespansPerTask)
    {
        this.concurrentLifespansPerTask = concurrentLifespansPerTask;
        return this;
    }