private static Result toResult(long reqId, com.yahoo.messagebus.Result mbusResult) {
        if (mbusResult.isAccepted()) {
            return new Result(reqId);
        }
        return new Result(
                messageBusErrorToResultType(mbusResult.getError().getCode()), mbusResult.getError());
    }
Returns a concatenated error string from the errors contained in a reply.

@param reply The reply whose errors to concatenate.
@return The error string.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/MessageBusAsyncSession.java