as does tab$a, i.e. just trying to extract the ChunkedArray.
Table$create(data.frame(b=1), schema = schema(a = int32())) creates a Table with column named a, overwriting the "b" column name.
tab <- Table$create(data.frame(b=2, c=3), schema = schema(a = int32())), i.e. providing fewer fields in the schema than there are columns in the data, segfaults.
There should be some validation that the schema matches the data provided.