<p>
A single channel may be used in
<a href="#Send_statements">send statements</a>,
<a href="#Receive_operator">receive operations</a>,
and calls to the built-in functions
<a href="#Length_and_capacity"><code>cap</code></a> and
<a href="#Length_and_capacity"><code>len</code></a>
by any number of goroutines without further synchronization.
Channels act as first-in-first-out queues.
For example, if one goroutine sends values on a channel