Problem: Total Area of Overlapping Rectangles

You are given two rectangles situated on a 2-D coordinate plane, which may overlap. Your task is to compute the total area covered by these rectangles.

Input:

The first line of input holds an integer 'T', indicating the number of test cases.
For each test case:
First line: Four integers 'x1', 'y1', 'x2', 'y2' - top-left and bottom-right coordinates of the first rectangle.
Second line: Four integers 'x3', 'y3', 'x4', 'y4' - top-left and bottom-right coordinates of the second rectangle.

Output:

Return an integer for each test case, representing the total area covered by the two rectangles.

Example:

Assuming rectangle coordinates and scenarios are illustrated with examples, as depicted in accompanying diagrams (not displayed here).

Constraints:

• 1 ≤ T ≤ 10^5
• -10^9 ≤ x1, y1, x2, y2 ≤ 10^9
• x1 < x2, x3 < x4
• y1 > y2, y3 > y4
• Time Limit: 1 second

Note:

Edges of rectangles are aligned parallel to the X and Y axes.