This is a polyfill that adds support for Node.js's `crypto.randomFill` and `crypto.randomFillSync` functions in older versions of Node.js (prior to v6.13.0). It's intended for developers who need these specific cryptographic random number generation functions but are working with legacy Node.js environments. The polyfill provides the same API as the native Node.js functions but isn't optimized for performance, so users are encouraged to use `crypto.randomBytes` directly if possible.