https://www.youtube.com/watch?v=DIPQ35Kg3-A


which borrows its first line (and borrows, but exaggerates the flow) from this one from 1926:

https://www.youtube.com/watch?v=aPrnbGm7jas


but perhaps the most rappity rap of all these early ones is probably Emmett Miller's blackface number The Gypsy from 1936 (the modern-style flow follows the dozens-style intro, comes in at 1:33):

https://www.youtube.com/watch?v=myBiO44B778