Constant mz_aws_util::s3_uploader::AWS_S3_MIN_PART_SIZE

const AWS_S3_MIN_PART_SIZE: ByteSize;

The minimum size of a part in a multipart upload.

This minimum doesn’t apply to the last chunk, which can be any size.

From https://docs.aws.amazon.com/AmazonS3/latest/userguide/qfacts.html