Expanding samples (bands) in a zarr sink does work

[manthey]

If you have a zarr sink and create an image one sample at a time, when we expand the array to accommodate a larger number of samples, the array fails to behave as expected.

Here is an example of the error:

import large_image
import numpy as np

sink = large_image.new()
for band in range(0, 10, 1):
    data = np.zeros((2000, 2000))
    data.fill(band)
    sink.addTile(data, s=band)
sink.write('test1.tiff')


sink = large_image.new()
for band in range(9, -1, -1):
    data = np.zeros((2000, 2000))
    data.fill(band)
    sink.addTile(data, s=band)
sink.write('test2.tiff')


ts1 = large_image.open('test1.tiff')
print(ts1.getRegion(format='numpy')[0][100, 100, 8])
# WRONG: prints np.uint8(0)

ts2 = large_image.open('test2.tiff')
print(ts2.getRegion(format='numpy')[0][100, 100, 8])
# RIGHT: prints np.uint8(8)