SftpClient.copyData

SftpOperation!bool copyData(const(ubyte)[]  readHandle,  ulong  readOffset,
           ulong  readLength,  const(ubyte)[]  writeHandle,  ulong  writeOffset)

Copies data server-side between two open handles through the copy-data extension version 1 (note: no vendor suffix in the extension name).

A readLength of zero copies from readOffset to the end of the source file. Both handles must be open on this client's channel and outlive the operation; the source handle needs read access and the destination handle write access. Overlapping ranges on the same handle follow the server's semantics. No client-side fallback is attempted when the server lacks the extension.

Known server quirk: OpenSSH (at least through 10.2) reports OK for an explicit-length copy whose final write chunk failed, so applications needing confirmation should verify the destination size or content afterwards.

Parameters

`readHandle`	Handle opened for reading.
`readOffset`	Source position.
`readLength`	Byte count, or zero to copy to end of file.
`writeHandle`	Handle opened for writing.
`writeOffset`	Destination position.

Returns

An operation completed by the server status response.

Throws

SftpException when the extension is not advertised

under its exact name or its version is not 1.