BunFetchRequestInit.s3

const response = await fetch("s3://bucket/key", {
  s3: {
    accessKeyId: "AKIAIOSFODNN7EXAMPLE",
    secretAccessKey: "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY",
    region: "us-east-1",
  }
});