The select keyword
The select keyword is really important because it allows you to listen to multiple channels at the same time. A select block can have multiple cases and an optional default case, which mimics the switch statement. It is good for select blocks to have a timeout option just in case. Lastly, a select without any cases (select{}) waits forever.
In practice, this means that select allows a goroutine to wait on multiple communication operations. So, select gives you the power to listen to multiple channels using a single select block. Consequently, you can have non-blocking operations on channels, provided that you have implemented your select blocks appropriately.
A select statement is not evaluated sequentially, as all of its channels are examined simultaneously. If none of the channels in a select statement are ready, the select statement blocks (waits) until one of the channels is ready. If multiple channels of a select statement are ready, then the Go runtime...
