BeginMultipartUploadParams

{
  "accountId": String,
  "beginMultipartUploadRequest": BeginMultipartUploadRequest
}

{
  "accountId": "YOUR_ACCOUNT_ID",
  "beginMultipartUploadRequest": {
    "metadata": {
      "myCustomField1": true,
      "myCustomField2": {
        "hello": "world"
      },
      "anotherCustomField": 42
    },
    "mime": "text/plain",
    "originalFileName": "example.txt",
    "path": {
      "fileName": "example-{UNIQUE_DIGITS_4}{ORIGINAL_FILE_EXT}",
      "folderPath": "/uploads"
    },
    "protocol": "1.0",
    "size": 43182,
    "tags": [
      "example_tag"
    ]
  }
}