isPossiblePrimaryKeyElement

Can the field be used as part of a primary key?

For this to be possible,

1. the field needs to be part of a key as defined by the source,

2. and its values must be deserializable from the checkpoint persisted in an Airbyte state message.

This method does not determine (1), of course, because the source keys are defined in the source database itself and are retrieved via MetadataQuerier.primaryKey. Instead, this method determines (2) based on the type information of the field, typically the FieldType objects. For instance if the Field.type does not map to a LosslessFieldType then the field can't reliably round-trip checkpoint values during a resumable initial sync.