fix(rust): writer missing invariants feature

[kallydev]

Description

The default version of Writer is 2, but the global ProtocolChecker is missing the invariants feature, which causes ProtocolChecker::can_write_to to return an UnsupportedWriterFeatures error. The error prevents me from passing false to the nullable field of StructField::new without the use of the datafunction feature.

Error: Transaction failed: Unsupported writer features required: [Invariants]

Caused by:
    Unsupported writer features required: [Invariants]

Related Issue(s)

• Resolved Unable to append to delta table without datafusion feature #2204
• Resolved Unable to write batch due to unsupported writer feature invariants (when datafusion flag is not enabled) #2292.

Documentation

delta-rs/crates/core/src/operations/transaction/protocol.rs

Lines 68 to 70 in d49d95b

	pub fn default_writer_version(&self) -> i32 {
	2
	}

delta-rs/README.md

Lines 159 to 164 in d49d95b

	### Protocol Support Level
	| Writer Version | Requirement | Status |
	| -------------- | --------------------------------------------- | :-------------------------------: |
	| Version 2 | Append Only Tables | ![done] |
	| Version 2 | Column Invariants | ![done] |

[ion-elgreco]

@kallydev it needs to be behind a Datafusion feature flag since invariants uses Datafusion to check the record batches according to the predicates

[kallydev]

@kallydev it needs to be behind a Datafusion feature flag since invariants uses Datafusion to check the record batches according to the predicates

OK, it seems like this is not an error. Thanks for your review! :)