ROS 2 .msg → CDR decoder for mcap2arrow.

Implements [MessageDecoder] for the (schema_encoding = ros2msg, message_encoding = cdr) key.

Unlike the IDL decoder, a .msg schema is a single file, so no multi-section bundle splitting is needed. builtin_interfaces types (Time, Duration) are injected automatically via [resolve_single_struct].

Pipeline

schema bytes (UTF-8 .msg)
  └─ parse_msg             – re_ros_msg parser → StructDef
      └─ resolve_single_struct  – type resolution → ResolvedSchema
          └─ decode_cdr_to_value – CDR bytes → Value