disable xray at runtime

On my django project, xray is configured to trace db queries.

In this use casem is it possible to disable / re-enable xray at runtime? What I want to do is,

```
from aws_xray_sdk import global_sdk_config

global_sdk_config.set_sdk_enabled(False) # Disable xray

## Do stuff with xray disabled

del os.environ['AWS_XRAY_SDK_ENABLED'] # Re-enable xray
global_sdk_config.set_sdk_enabled(True)
```

When I run the code like this, I still get error logs from xray (and my main problem is addressed here: https://github.com/aws/aws-xray-sdk-python/issues/21 , but the suggested solution did not solve the issue for me)

And I could not understand from the docs whether
`global_sdk_config.set_sdk_enabled(False)`
would disable xray at runtime or if it was designed to disable xray before running an application.