Function isValidMqttString

isValidMqttString(str: string): boolean
Validates that a string is valid for MQTT UTF-8 encoding.

MQTT places restrictions on UTF-8 strings beyond standard UTF-8:
- No null characters (U+0000)
- No control characters U+0001 to U+001F
- No control characters U+007F to U+009F
Parameters
- str: string
  The string to validate
Returns boolean
true if the string is valid for MQTT

See
MQTT 5.0 §1.5.4
- Defined in codec/utf8.ts:65