How to calculate identical hashes in React Native and Node?

I'm using `hash` to generate checksums for files before I upload them to AWS S3.

```javascript
RNFS.hash(localUrl, "md5")
```
This seems to work great. Once the file has been uploaded, I need to verify the checksum for the file using Node 10.x (Lambda). I can't seem to get the same checksum using other libraries. For example, with Node's [crypto.createHash](https://nodejs.org/api/crypto.html#crypto_crypto_createhash_algorithm_options):

```javascript
const file = await s3
.getObject({
Bucket,
Key
}).promise()

crypto
.createHash("md5")
.update(file.Body)
.digest("hex");
```

The generated hash does not match what was produced by `react-native-fs`. How do I generate a hash in Node identical to what is produced by `react-native-fs` for the same file?