call-limit
----------
Limit the number of simultaneous executions of a async function.
```javascript
const fs = require('fs')
const limit = require('call-limit')
const limitedStat = limit(fs.stat, 5)
```
Or with promise returning functions:
```javascript
const fs = Bluebird.promisifyAll(require('fs'))
const limit = require('call-limit')
const limitedStat = limit.promise(fs.statAsync, 5)
```
### USAGE:
Given that:
```javascript
const limit = require('call-limit')
```
### limit(func, maxRunning) → limitedFunc
The returned function will execute up to maxRunning calls of `func` at once.
Beyond that they get queued and called when the previous call completes.
`func` must accept a callback as the final argument and must call it when
it completes, or `call-limit` won't know to dequeue the next thing to run.
By contrast, callers to `limitedFunc` do NOT have to pass in a callback, but
if they do they'll be called when `func` calls its callback.
### limit.promise(func, maxRunning) → limitedFunc
The returned function will execute up to maxRunning calls of `func` at once.
Beyond that they get queued and called when the previous call completes.
`func` must return a promise.
`limitedFunc` will return a promise that resolves with the promise returned
from the call to `func`.
### limit.method(class, methodName, maxRunning)
This is sugar for:
```javascript
class.prototype.methodName = limit(class.prototype.methodName, maxRunning)
```
### limit.method(object, methodName, maxRunning)
This is sugar for:
```javascript
object.methodName = limit(object.methodName, maxRunning)
```
For example `limit.promise.method(fs, 'stat', 5)` is the same as
`fs.stat = limit.promise(fs.stat, 5)`.
### limit.promise.method(class, methodName, maxRunning)
This is sugar for:
```javascript
class.prototype.methodName = limit.promise(class.prototype.methodName, maxRunning)
```
### limit.promise.method(object, methodName, maxRunning)
This is sugar for:
```javascript
object.methodName = limit.promise(object.methodName, maxRunning)
```
For example `limit.promise.method(fs, 'statAsync', 5)` is the same as
`fs.statAsync = limit.promise(fs.statAsync, 5)`.
