code: @GuardedBy("lock")
      private Request findOverlappingRequest(Request request) {
          Map.Entry<Long, Request> previousEntry = this.pendingRequests.floorEntry(request.getOffset());
          if (previousEntry != null && request.getOffset() < previousEntry.getValue().getEndOffset()) {
              // Found one.
              return previousEntry.getValue();
          }
  
          // Either no previous entry, or the highest previous entry does not overlap.
          return null;
      }
docs: Finds a pending Request that overlaps with the given request, based on the given request's Offset.
  
  @param request The request.
  @return The overlapping request, or null if no such request exists.