A single keyframe that can be injected into an animation curve.
| inTangent | Describes the tangent when approaching this point from the previous point in the curve. |
| outTangent | Describes the tangent when leaving this point towards the next point in the curve. |
| time | The time of the keyframe. |
| value | The value of the curve at keyframe. |
| Keyframe | Create a keyframe. |