This is the code I am using:
private fun SetKeywordStatus(keywordId: Long, adGroupId: Long, status: UserStatus)
{
val keyword = Criterion()
keyword.id = keywordId
val keywordBiddableAdGroupCriterion = BiddableAdGroupCriterion()
keywordBiddableAdGroupCriterion.adGroupId = adGroupId
keywordBiddableAdGroupCriterion.criterion = keyword
keywordBiddableAdGroupCriterion.userStatus = status
// Create operations.
val operation = AdGroupCriterionOperation()
operation.operand = keywordBiddableAdGroupCriterion
operation.operator = Operator.SET
val result = adGroupCriterionService.mutate(arrayOf(operation))
for (result in result.value) {
println("KeywordId ${keywordId} had its status changed")
}
}