Please fix for this Err: on Thai and Lao lang

[Seng555]

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Invalid argument (string): Contains invalid characters.: "ສິນຄ້າ"
#0 _UnicodeSubsetEncoder.convert (dart:convert/ascii.dart:85:9)
#1 Latin1Codec.encode (dart:convert/latin1.dart:40:46)
#2 Generator._encode (package:esc_pos_utils_plus/src/generator.dart:78:21)
#3 Generator.text (package:esc_pos_utils_plus/src/generator.dart:355:9)
#4 _MyAppState._printReceiveTest (package:printest/main.dart:164:24)

[Abhis1211]

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Invalid argument (string): Contains invalid characters.: "जीन्स पैंट नैरो"

how to print hindi word ?

[Seng555]

Where support ?