OUT endpoint callback does not get called when the data size is less than maximum

[dogtopus]

I'm trying to implement USB mass storage class in user mode so I could build upon that to experiment with proprietary SCSI CDBs. Reading seems to work well, except that when a write request is less than the maximum possible amount (usually out_aio_blocks_per_endpoint * out_aio_blocks_max_packet_count but when both are 1 it's somehow 1024 bytes instead of 512 when working under high speed mode) the EndpointOUTFile.onComplete callback will not get called.

I don't think EndpointOUTFile has any complex logic in it on its own so maybe this is an issue in libaio or an issue caused by some misconfiguration of libaio?

Some background: This is over USB HighSpeed with 512 bytes max packet size, default out_aio_blocks_per_endpoint and out_aio_blocks_max_packet_count, and with a custom build of libaio 0.3.113 targeting glibc 2.34.

Also all the CBWs seem to arrive just fine. It's only the data that got truncated.