Sends a key-off command for the note playing on the specified channel. This method releases envelopes and sample sustain loops. If the sample has no sustain loop, or if the module does not use instruments, it does nothing.

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate int ModuleExtInterfaceInteractive2.NoteOffDelegate(IntPtr modExt, int channel) : 
    MulticastDelegate, ICloneable, ISerializable