Unity editor, horizontal line in the inspector

Public static class EditorGUILayoutUtility
{
public static readonly Color DEFAULT_COLOR = new Color (0f, 0f, 0f, 0.3f);
public static read-only Vector2 DEFAULT_LINE_MARGIN = new Vector2 (2f, 2f);

public const float DEFAULT_LINE_HEIGHT = 1f;

public static vacuum HorizontalLine (color, float height, margin Vector2)
{
GUILayout.Space (margin.x);

EditorGUI.DrawRect (EditorGUILayout.GetControlRect (false, height), color);

GUILayout.Space (margin.y);
}
blank static public HorizontalLine (Color Color, Floating Height) => EditorGUILoutUtility.HorizontalLine (color, height, DEFAULT_LINE_MARGIN);
blank static public HorizontalLine (Color color, Vector2 margin) => EditorGUILoutUtility.HorizontalLine (color, DEFAULT_LINE_HEIGHT, margin);
public static static HorizontalLine (float height, Vector2 margin) => EditorGUILoutoutUtility.HorizontalLine (DEFAULT_COLOR, height, margin);

public static empty HorizontalLine (Color color) => EditorGUILoutoutUtility.HorizontalLine (color, DEFAULT_LINE_HEIGHT, DEFAULT_LINE_MARGIN);
public static static HorizontalLine (float height) => EditorGUILoutoutUtility.HorizontalLine (DEFAULT_COLOR, height, DEFAULT_LINE_MARGIN);
public static static HorizontalLine (Vector2 margin) => EditorGUILoutoutUtility.HorizontalLine (DEFAULT_COLOR, DEFAULT_LINE_HEIGHT, margin);

public static empty HorizontalLine () => EditorGUILayoutUtility.HorizontalLine (DEFAULT_COLOR, DEFAULT_LINE_HEIGHT, DEFAULT_LINE_MARGIN);

#if UNITY_EDITOR
#end if
}

Call:

public override void OnInspectorGUI ()
{
base.OnInspectorGUI ();

EditorGUILayout.BeginVertical ();

EditorGUILayoutUtility.HorizontalLine (new Vector2 (20f, 20f));

EditorGUILayout.EndVertical ();
}

Will give this result.

Draw a line Result