Writing an AVRO enum field with an invalid value generates unhelpful NPE

When an enum field is written with a symbol that is not one of the valid enum symbols configured in the schema, the code generates a NPE which turns into a null value message which is not extremely helpful. It would be useful if the message mentioned the invalid symbol and the available symbols from the schema.

Here's a sample of the generated stack trace.  More in the attachment:

java.lang.NullPointerException: null value for (non-nullable) enum1 at record1.field1
     ...
Caused by: java.lang.NullPointerException
     at org.apache.avro.Schema$EnumSchema.getEnumOrdinal(Schema.java:1118)
...