RxJava 2.x 理解-2

操作符总结：http://reactivex.io/documentation/operators.html

Operators By Category

Creating Observables

Operators that originate new Observables.

• Create — create an Observable from scratch by calling observer methods programmatically
•            —  基本创建方式
• Defer — do not create the Observable until the observer subscribes, and create a fresh Observable for each observer
•          — 当观察者订阅时，才创建Observable，而不是像Create一样，执行Create就创建好了，在subscribe时才创建这个对象。并且针对每个观察者创建都是一个新的Observable。 RxJava的懒加载，慎重使用自定义操作符，优先考虑内置操作符
• Empty/Never/Throw — create Observables that have very precise and limited behavior
• From — convert some other object or data structure into an Observable
• Interval — create an Observable that emits a sequence of integers spaced by a particular time interval
• Just — convert an object or a set of objects into an Observable that emits that or those objects
• Range — create an Observable that emits a range of sequential integers
• Repeat — create an Observable that emits a particular item or sequence of items repeatedly
• Start — create an Observable that emits the return value of a function
• Timer — create an Observable that emits a single item after a given delay