in src/SigV4RequestSigner.ts [201:208]
private static toUint8Array(input: string): Uint8Array {
const buf = new ArrayBuffer(input.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = input.length; i < strLen; i++) {
bufView[i] = input.charCodeAt(i);
}
return bufView;
}