The Future class from dart:async lies in the basis of all asynchronous programming in Dart. A Future is, in fact, a computation that is deferred; it represents an object whose value will be available sometime in the future. It is not available immediately, because the function that returns its value depends on some kind of input/output and is, thus, unpredictable by nature. Here are some examples: a time-consuming computation, reading in a big dataset, and searching through a number of websites.
In the two previous chapters, quite a lot of recipes used Futures; in Chapter 6, Working with Files and Streams, we had the following recipes using Futures:
Reading and processing a file line by line
Concatenating files the asynchronous way
Downloading a file
In the preceding chapter, we used Futures in the following recipes:
Making a web server
Receiving data on the web server
Using sockets
In this chapter, we will concentrate on how to write elegant code for Futures and combine...