Read data from an evbuffer into another evbuffer, draining
the bytes from the source buffer. This function avoids copy
operations to the extent possible.
If more bytes are requested than are available in src, the src
buffer is drained completely.
@param src the evbuffer to be read from
@param dst the destination evbuffer to store the result into
@param datlen the maximum numbers of bytes to transfer
@return the number of bytes read
Read data from an evbuffer into another evbuffer, draining the bytes from the source buffer. This function avoids copy operations to the extent possible.
If more bytes are requested than are available in src, the src buffer is drained completely.
@param src the evbuffer to be read from @param dst the destination evbuffer to store the result into @param datlen the maximum numbers of bytes to transfer @return the number of bytes read