Commented Unassigned: System.OutOfMemoryException when trying large files in sftp [1866]

Exception of type 'System.OutOfMemoryException' was thrown.
mscorlib
at System.IO.MemoryStream.set_Capacity(Int32 value)
at System.IO.MemoryStream.EnsureCapacity(Int32 value)
at System.IO.MemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at Renci.SshNet.SftpClient.InternalDownloadFile(String path, Stream output, SftpDownloadAsyncResult asyncResult, Action`1 downloadCallback)

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Multiple files of 400MB or 1GB files.
The entire file is in the stream object that could be the problem.
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Comments: ** Comment from web user: chenthil_it **

thanks for the reply.
But the sftpfile stream is very slow it took 1hr 15 mins for 400mb file. I tried changing the buffer size but no success. Is there any transfer limit in sftpfilestream.