Generate proper initializers for variables corresponding to required primitive fields when @ProtoFactory is used

static final class AlphaColor {

 private final int r;

 private final int g;

 private final int b;

 private final float transparency;

 @ProtoFactory
 public AlphaColor(int r, int g, int b, float transparency) {
 this.r = r;
 this.g = g;
 this.b = b;
 this.transparency = transparency;
 }

 @ProtoField(number = 1, required = true)
 public int getR() {
 return r;
 }

 @ProtoField(number = 2, required = true)
 public int getG() {
 return g;
 }

 @ProtoField(number = 3, required = true)
 public int getB() {
 return b;
 }

 @ProtoField(number = 4, required = true)
 public float getTransparency() {
 return transparency;
 }
}