allocator to be used for this memory
file descriptor
memory size
extra #GstFdMemoryFlags
a GstMemory based on allocator. When the buffer will be released the allocator will close the fd unless the GST_FD_MEMORY_FLAG_DONT_CLOSE flag is specified. The memory is only mmapped on gst.buffer.Buffer.map request.
Return a gst.memory.Memory that wraps a generic file descriptor.