Function buildRequestBody

buildRequestBody(
payload: Record<string, unknown>,
): { body: BodyInit; headers?: Record<string, string> }
Builds either a JSON string body or a FormData multipart body for Telegram Bot API requests.

Automatically inspects the payload properties for binary InputFile or Blob instances:
- If binary data is present, serializes as multipart FormData.
- If only primitive/JSON data is present, serializes as JSON with application/json header.
Parameters
- payload: Record<string, unknown>
  Key-value map of parameters to send with the Telegram API request.
Returns { body: BodyInit; headers?: Record<string, string> }
Object containing the serialized body and optional request headers.
Example
```
const { body, headers } = buildRequestBody({ chat_id: 12345, text: "Hello!" });
```