NewReader creates a new Reader for use in Unilog. Once shutdown becomes readable, the
returned Reader will start reading from the underlying Reader one
byte at a time until newline, and then start returning EOF.
type Reader struct {
// contains filtered or unexported fields
}
Reader wraps an existing io.Reader and adds the ability to
perform a graceful shutdown by reading from the underlying Reader
up through the next newline character, and then start returning
EOF.