Merge branch 'main' of https://github.com/dallison/cpp_toolbelt

Add bitmap allocator to PayloadBuffer

This uses a bitmap allocator (optionally) for allocation of small blocks
up to 128 bytes.  It's about twice the speed of the simple allocator
for these block sizes, as the expense of extra memory in the buffer.

Switch off bitmap allocator for now

Fix resize

PayloadBuffer::AllocateMany

Add missing includes

Add PayloadBuffer class

Use latest coroutines release

Fix sockets with invalid address

Fix build breakage