Function ChunkedOutputStream.chunkExtensionCallback
A delegate used to specify the extensions for each chunk written to the underlying stream.
@safe string delegate(in ubyte[]) chunkExtensionCallback() @property @safe const;
void chunkExtensionCallback
(
@safe string delegate(in ubyte[]) cb
) @property @safe;
The delegate has to be of type string delegate(in const(ubyte)[] data) and gets handed the
data of each chunk before it is written to the underlying stream. If it's return value is non-empty,
it will be added to the chunk's header line.
The returned chunk extension string should be of the format key1=value1;key2=value2;[...];keyN=valueN
and **not contain any carriage return or newline characters**.
Also note that the delegate should accept the passed data through a scoped argument. Thus, **no references to the provided data should be stored in the delegate**. If the data has to be stored for later use, it needs to be copied first.