EP2PSend

Reliable message send. Can send up to 1MB of data in a single message. Does fragmentation/re-assembly of messages under the hood, as well as a sliding window for efficient sends of large chunks of data.

As above, but applies the Nagle algorithm to the send - sends will accumulate until the current MTU size (typically ~1200 bytes, but can change) or ~200ms has passed (Nagle algorithm). Useful if you want to send a set of smaller messages but have the coalesced into a single packet Since the reliable stream is all ordered, you can do several small message sends with k_EP2PSendReliableWithBuffering and then do a normal k_EP2PSendReliable to force all the buffered data to be sent.

Basic UDP send. Packets can't be bigger than 1200 bytes (your typical MTU size). Can be lost, or arrive out of order (rare). The sending API does have some knowledge of the underlying connection, so if there is no NAT-traversal accomplished or there is a recognized adjustment happening on the connection, the packet will be batched until the connection is open again.

As above, but if the underlying p2p connection isn't yet established the packet will just be thrown away. Using this on the first packet sent to a remote host almost guarantees the packet will be dropped. This is only really useful for kinds of data that should never buffer up, i.e. voice payload packets