Extracts exception details, if and only if it's
an erroneous WriteResult.
import reactivemongo.api.commands.WriteResult
def printRes(res: WriteResult): Unit = res match {
case WriteResult.Exception(cause) =>
cause.printStackTrace()
case _ =>
println(s"OK: " + res)
}
Extracts exception details, if and only if it's an erroneous WriteResult.