[Bug]: Memory leak detected when repeatedly processing images

[Chanstien]

test_sdpc.py example:

from opensdpc import OpenSdpc

if __name__ == "__main__":
    for _ in range(1000):
        slide = OpenSdpc("./20220514_145829_0.sdpc")
        slide.close()

memray:

memray run --output memory_profile.bin ./test_sdpc.py
memray summary memory_profile.bin