Writer  // includes methods of Writer in ReadWriter's method set
}
</pre>

<p>
A <i>union</i> of method sets contains the (exported and non-exported)
methods of each method set exactly once, and methods with the
<a href="#Uniqueness_of_identifiers">same</a> names must
have <a href="#Type_identity">identical</a> signatures.
</p>

<pre>
type ReadCloser interface {

<p>
In its most basic form an interface specifies a (possibly empty) list of methods.
The type set defined by such an interface is the set of types which implement all of
those methods, and the corresponding <a href="#Method_sets">method set</a> consists
exactly of the methods specified by the interface.
Interfaces whose type sets can be defined entirely by a list of methods are called
<i>basic interfaces.</i>
</p>

<pre>