copyInto method
Copy this into arg.
Implementation
Matrix2 copyInto(Matrix2 arg) {
final Float64List argStorage = arg._m2storage;
argStorage[0] = _m2storage[0];
argStorage[1] = _m2storage[1];
argStorage[2] = _m2storage[2];
argStorage[3] = _m2storage[3];
return arg;
}