This callback is used to retrieve the next chunk of data for a streaming
contents buffer created with #epc_contents_stream_read.
Return %FALSE when the buffer has reached its end, and no more data is
available. Also return %FALSE, when the buffer size passed in length is
not sufficient. Copy your minimal buffer size to length in that situation.
The library might pass %NULL for buffer on the first call to start buffer
size negotation.
See also: #epc_contents_stream_new, #epc_contents_stream_read
This callback is used to retrieve the next chunk of data for a streaming contents buffer created with #epc_contents_stream_read.
Return %FALSE when the buffer has reached its end, and no more data is available. Also return %FALSE, when the buffer size passed in
lengthis not sufficient. Copy your minimal buffer size tolengthin that situation.The library might pass %NULL for
bufferon the first call to start buffer size negotation.See also: #epc_contents_stream_new, #epc_contents_stream_read