setFrom method
Sets the entire matrix to the matrix in arg.
Implementation
void setFrom(Matrix2 arg) {
final Float32List argStorage = arg._m2storage;
_m2storage[3] = argStorage[3];
_m2storage[2] = argStorage[2];
_m2storage[1] = argStorage[1];
_m2storage[0] = argStorage[0];
}