serialize method
Implementation
@override
ByteData serialize() {
var data_ = ByteData(mavlinkEncodedLength);
data_.setInt16(0, startIndex, Endian.little);
data_.setInt16(2, endIndex, Endian.little);
data_.setUint8(4, targetSystem);
data_.setUint8(5, targetComponent);
data_.setUint8(6, missionType);
return data_;
}