The element count for an array field, or 0 for a scalar.
Whether this is a MAVLink 2 extension field.
The field's type, one of the MAVLINK_FIELD_* codes.
The field name as the dialect writes it, such as custom_mode.
The field's byte offset within the payload.
The field's type name as the dialect writes it, such as uint32_t.
One field of a message shape.