A pilot on short final approach reported a NMAC in the traffic pattern with an aircraft on base leg.

Narrative

I was on a long final coming into Hanscom field BED. I noticed on my ADSB EFB that there was a plane on a right base at the same altitude that looked like it would arrive to final at the same time as me. ATC was directing them to find me visually as traffic; but even as such I felt ATC was vectoring them very close to me. I found the other plane visually and continued my final and looked to see what options I had if they didn't turn. There were planes on the left downwind so I didn't feel that would be a safe turn. Eventually as the plane got pretty close; I elected to descend rapidly to avoid it as it would have narrowly passed behind me. The other plane also turned left to pass behind me as collision avoidance. Afterwards I got back to a normal glidepath and landed normally. The other plane was too close behind me on final so they went around. I believe the cause of the incident was that ATC did not properly sequence our two planes to have proper separation for landing. The other plane should have been directed to turn onto a downwind instead of a direct base to final.