Returns the data contained in this part in the form of an Observable that a subscriber can subscribe to.
Returns the data contained in this part in the form of an Observable that a subscriber can subscribe to. This function should createReader a clean rows on each invocation. By clean, we mean that each seperate rows should provide the full set of data contained in the part, in a thread safe manner. Ie, it should be possible to invoke this method k times, and subscribe to those k observables concurrently, and each rows should emit the same data.
A Part represents part of the source data. Eg a single file in a multi-file source, or a single table in a multi-table source. Splitting sources into parts allows them to be read concurrently, therefore, implementations must ensure that different parts can be safely read in parallel. A single part is always read by a single thread.