Function parse

parse(content: string): { mimeType: string; description: string }
Parser for payload tags - defines MQTT message payload type and description

This parser handles the payload tag that defines MQTT message payload format. It extracts:
- MIME type (application/json, text/plain, etc.)
- Optional description of payload content
Parameters
- content: string
  Raw content from the payload tag
Returns { mimeType: string; description: string }
Parsed payload information with mimeType and description, or null if parsing fails
Example: JSON payload
```
// Input: "application/json Device telemetry data"
// Output: { mimeType: "application/json", description: "Device telemetry data" }
```
Example: Plain text payload
```
// Input: "text/plain Simple status message"
// Output: { mimeType: "text/plain", description: "Simple status message" }
```
Example: Binary payload
```
// Input: "application/octet-stream Binary sensor data"
// Output: { mimeType: "application/octet-stream", description: "Binary sensor data" }
```
Example: MIME type only
```
// Input: "application/xml"
// Output: { mimeType: "application/xml", description: "" }
```
Since
4.1.0

Public
- Defined in core/parsers/mqtt_payload.ts:39