Error retriving characters with non-UTF8 encoding

[lewiszlw]

Here is oracle nls_database_parameters table data

+-------------------------+------------------------------+
| PARAMETER               | VALUE                        |
+-------------------------+------------------------------+
| NLS_LANGUAGE            | AMERICAN                     |
| NLS_TERRITORY           | AMERICA                      |
| NLS_CURRENCY            | $                            |
| NLS_ISO_CURRENCY        | AMERICA                      |
| NLS_NUMERIC_CHARACTERS  | .,                           |
| NLS_CHARACTERSET        | ZHS16GBK                     |
| NLS_CALENDAR            | GREGORIAN                    |
| NLS_DATE_FORMAT         | DD-MON-RR                    |
| NLS_DATE_LANGUAGE       | AMERICAN                     |
| NLS_SORT                | BINARY                       |
| NLS_TIME_FORMAT         | HH.MI.SSXFF AM               |
| NLS_TIMESTAMP_FORMAT    | DD-MON-RR HH.MI.SSXFF AM     |
| NLS_TIME_TZ_FORMAT      | HH.MI.SSXFF AM TZR           |
| NLS_TIMESTAMP_TZ_FORMAT | DD-MON-RR HH.MI.SSXFF AM TZR |
| NLS_DUAL_CURRENCY       | $                            |
| NLS_COMP                | BINARY                       |
| NLS_LENGTH_SEMANTICS    | BYTE                         |
| NLS_NCHAR_CONV_EXCP     | FALSE                        |
| NLS_NCHAR_CHARACTERSET  | AL16UTF16                    |
| NLS_RDBMS_VERSION       | 11.2.0.4.0                   |
+-------------------------+------------------------------+

I set env NLS_LANG=AMERICAN_AMERICA.AL32UTF8 for client. I got error OCI Error: ORA-29275: partial multibyte character when retriving varchar2 column. Is there any way this library or oracle database could auto convert non-utf8 characters to utf8 characters? Or I can try to get raw data and encoding info(maybe need https://github.com/kubo/rust-oracle/pull/55) and do convertion myself?