Writers and readers are not just for files; they are interfaces that abstract flows of data in one direction or another. These flows, often referred to as streams, are an essential part of most applications.
Streams
Input and readers
Incoming streams of data are considered the io.Reader interface if the application has no control over the data flow, and will wait for an error to end the process, receiving the io.EOF value in the best case scenario, which is a special error that signals that there is no more content to read, or another error otherwise. The other option is that the reader is also capable of terminating the stream. In this case, the correct representation is the io.ReadCloser ...
