Configuration for request-el (Mastering Emacs

Variables
request-storage-directory
Directory to store data related to request.el.
```
request-storage-directory "~/.emacs.d/request"
```
request-curl
Executable for curl command.
```
request-curl "curl"
```
request-backend
Backend to be used for HTTP request. Automatically set to curl if curl command is found.
```
request-backend 'curl
```
request-timeout
Default request timeout in second. nil means no timeout.
```
request-timeout nil
```
request-log-level
Logging level for request. One of ‘error/warn/info/verbose/debug’. -1 means no logging.
```
request-log-level '-1
```
request-message-level
Logging level for request. See request-log-level
```
request-message-level 'warn
```