max int
	buf io.Reader
}

func (sr *slowReader) Read(p []byte) (n int, err error) {
	if len(p) > sr.max {
		p = p[0:sr.max]
	}
	return sr.buf.Read(p)
}

// genLine writes to buf a predictable but non-trivial line of text of length
// n, including the terminal newline and an occasional carriage return.
// If addNewline is false, the \r and \n are not emitted.

		s2c, cb := newS2CompressReader(actualReader, actualSize, wantEncryption)
		idxCb = cb
		defer s2c.Close()
		reader = etag.Wrap(s2c, actualReader)
		size = -1   // Since compressed size is un-predictable.
		md5hex = "" // Do not try to verify the content.
		sha256hex = ""
	}

	var forceMD5 []byte
	// Optimization: If SSE-KMS and SSE-C did not request Content-Md5. Use uuid as etag. Optionally enable this also

		s2c, idxCb = newS2CompressReader(actualReader, actualSize, wantEncryption)
		defer s2c.Close()

		reader = etag.Wrap(s2c, actualReader)
		size = -1   // Since compressed size is un-predictable.
		md5hex = "" // Do not try to verify the content.
		sha256hex = ""
	}

	var forceMD5 []byte
	// Optimization: If SSE-KMS and SSE-C did not request Content-Md5. Use uuid as etag. Optionally enable this also

// MD5 of the object. For multipart uploads the ETag is also not
// the MD5 of the individual part checksums but it still contains
// the number of parts as suffix.
//
// Instead, the ETag is kind of unpredictable for S3 clients when
// an object is encrypted using SSE-C or SSE-KMS. Maybe AWS S3
// computes the ETag as MD5 of the encrypted content but there is
// no way to verify this assumption since the encryption happens

It is possible to defeat this enforcement by using the unsafe package,
and of course there is nothing stopping the C code from doing anything
it likes. However, programs that break these rules are likely to fail
in unexpected and unpredictable ways.

The runtime/cgo.Handle type can be used to safely pass Go values
between Go and C. See the runtime/cgo package documentation for details.

Note: the current implementation has a bug. While Go code is permitted