size(in bytes) for the receive buffer in libcurl. The main point of this would be that the write callback gets called more often and with smaller chunks. Secondly, for some protocols, there's a benefit of having a larger buffer for performance.
This is just treated as a request, not an order. You cannot be guaranteed to actually get the given size.
This buffer size is by default
#CURL_MAX_WRITE_SIZE (16kB). The maximum
buffer size allowed to be set is
#CURL_MAX_READ_SIZE (512kB). The minimum
buffer size allowed to be set is 1024.