best way to copy a big binary file

[Skaperen]

i also want to be able to output a progress indicator, such as the number of bytes copied so far. that rules out using anything that carries out the whole copy before completing. i'm thinking of implementing my copier as a generator that yields an int of the number of byte copied so far.

for number_of_bytes in copy_gen(fin,fout):
    print(f'\r{number_of_bytes} ',end='',flush=True)