How to write if the quaternions are almost equal?

Question

Unity

You need to write a condition that, if the quaternions are equal or almost equal, then do the action

Answer 1

For example, you can calculate Quaternion.Angle and compare with some small value. Or take the distance between Quaternion.eulerAngles.

Answer 2

And the quaternion has components {x, y, z, w}, so compare their proximity.