startSpan
abstract fun startSpan(name: String, parent: EmbraceSpan? = null, startTimeMs: Long? = null, autoTerminationMode: AutoTerminationMode = AutoTerminationMode.NONE): EmbraceSpan(source)
Create, start, and return a new EmbraceSpan with the given name, parent, and start time (epoch time in milliseconds). Returns a noop instance if the span cannot be created or started, like if the parent has been started.