asAddHeaderOrNull
Casts this RuleAction as a AddHeader and retrieves its aws.sdk.kotlin.services.mailmanager.model.AddHeaderAction value. Returns null if the RuleAction is not a AddHeader.
Casts this RuleAction as a AddHeader and retrieves its aws.sdk.kotlin.services.mailmanager.model.AddHeaderAction value. Returns null if the RuleAction is not a AddHeader.