Without output.getvalue() the StringIO object will just accumulate references to s until it hits 100,000 references, at which point the internal buffer will actually be realized.
Currently, this benchmark can be run and do 99,999 .write() operations on the StringIO object but 99_999 * CHUNK_SIZE bytes are not written into memory as a single 99GB buffer.
Without
output.getvalue()the StringIO object will just accumulate references tosuntil it hits 100,000 references, at which point the internal buffer will actually be realized.Currently, this benchmark can be run and do 99,999
.write()operations on theStringIOobject but99_999 * CHUNK_SIZEbytes are not written into memory as a single 99GB buffer.