vimr: Crashing when writing beyond right window border

Steps to reliably reproduce the problem here:

set tw=0 set wrap go to insert mode in a new buffer (any file/buffer will do) keep spacebar (or any other character on the keyboard) pressed, so it repeats somewhat quickly

depending on the VimR window size, when hitting the right border of the window (just before it should wrap), VimR crashes with:

Exception Type:        EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes:       0x0000000000000001, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Illegal instruction: 4
Termination Reason:    Namespace SIGNAL, Code 0x4
Terminating Process:   exc handler [0]

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   com.qvacua.VimR.SwiftNeoVim   	0x000000010822cdc7 specialized Grid.put(_:) + 615
1   com.qvacua.VimR.SwiftNeoVim   	0x000000010823741c specialized closure #1 in NeoVimView.put(_:) + 92
2   com.qvacua.VimR.SwiftNeoVim   	0x00000001082361fc partial apply for closure #1 in NeoVimView.put(_:) + 76
3   libdispatch.dylib             	0x00007fff5dd1b7a2 _dispatch_call_block_and_release + 12
4   libdispatch.dylib             	0x00007fff5dd13f64 _dispatch_client_callout + 8
5   libdispatch.dylib             	0x00007fff5dd1f545 _dispatch_main_queue_callback_4CF + 1148
6   com.apple.CoreFoundation      	0x00007fff36789a09 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
7   com.apple.CoreFoundation      	0x00007fff3674c2ba __CFRunLoopRun + 2586
8   com.apple.CoreFoundation      	0x00007fff3674b607 CFRunLoopRunSpecific + 487
9   com.apple.HIToolbox           	0x00007fff35a60866 RunCurrentEventLoopInMode + 286
10  com.apple.HIToolbox           	0x00007fff35a605d6 ReceiveNextEventCommon + 613
11  com.apple.HIToolbox           	0x00007fff35a60354 _BlockUntilNextEventMatchingListInModeWithFilter + 64
12  com.apple.AppKit              	0x00007fff33d5d9f7 _DPSNextEvent + 2085
13  com.apple.AppKit              	0x00007fff344f2d98 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
14  com.apple.AppKit              	0x00007fff33d52805 -[NSApplication run] + 764
15  com.apple.AppKit              	0x00007fff33d219a6 NSApplicationMain + 804
16  com.qvacua.VimR               	0x0000000107e1f369 main + 9
17  libdyld.dylib                 	0x00007fff5dd4d145 start + 1

It does not crash reliably when typing text slowly.

Affected: Version 0.19.0 (226)