unity quaternion using a rotation vector

1. The vector into quaternion

Quaternion qua0=new Quaternion();
Debug.Log(qua0.eulerAngles);//输出：(0.0, 0.0, 0.0)

Quaternion qua1=Quaternion.LookRotation(Vector3.forward);
Debug.Log(qua1.eulerAngles);//输出：(0.0, 0.0, 0.0)

Quaternion qua2=Quaternion.LookRotation(new Vector3(1,0,0));
Debug.Log(qua2.eulerAngles);//输出： (0.0, 90.0, 0.0)

//向量(1,0,0)绕Y轴旋转90度。
Vector3 v3=new Vector3(1,0,0);
Vector3 result= Quaternion.AngleAxis(90, Vector3.up)*v3;
Debug.Log(result);//输出：(0.0, 0.0, -1)