def lines2 = [['Quick', 'Brown']]
echo "Literal toString():" + lines2
def result2 = ''
lines2.each{ result2 += it }
echo "Literal each: " + result2

@NonCPS def test(){
    def lines = ['Quick Brown'].collect{ it.split('\\s+') }
    echo "NonCps toString()" + lines
    def result = ''
    lines.each{ result += it }
    echo "NonCps each: " + result
}
test()

def lines = ['Quick Brown'].collect{ it.split('\\s+') }
echo "Collect toString():" + lines
def result = ''
lines.each{ result += it }
echo "Collect each: " + result

[Pipeline] echo
Literal toString():[[Quick, Brown]]
[Pipeline] echo
Literal each: [Quick, Brown]
[Pipeline] echo
NonCps toString()[[Quick, Brown]]
[Pipeline] echo
NonCps each: [Quick, Brown]
[Pipeline] echo
Collect toString():[[Quick, Brown]]
[Pipeline] echo
Collect each: Quick
[Pipeline] End of Pipeline
Finished: SUCCESS