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注意 if you need to seek and write to the stream, it does not make sense to use this function, because the stream it returns is not guaranteed to be bound to the same resource as the original stream.
an error occurred while attempting conversion that has left origstream in an indeterminate state. newstream is set to null and it is highly recommended that you close origstream.

php_stream_copy_to_stream() attempts to read up to maxlen bytes of data from src and write them to dest, and returns the number of bytes that were successfully copied.
php_stream_copy_to_stream() attempts to read up to maxlen bytes of data from src and write them to dest, and returns the number of bytes that were successfully copied.