do {
            if ( ( readn(this.in, this.sbuf, 0, 4) ) < 4 ) {
                return null;
            }
        }
        while ( this.sbuf[ 0 ] == (byte) 0x85 ); /* Dodge NetBIOS keep-alive */
        /* read smb header */
        if ( ( readn(this.in, this.sbuf, 4, SmbConstants.SMB1_HEADER_LENGTH) ) < SmbConstants.SMB1_HEADER_LENGTH ) {
            return null;
        }

            this.treeHandle.ensureDFSResolved();
            if ( this.transportContext.getConfig().isStrictResourceLifecycle() ) {
                // one extra share to keep the tree alive
                return this.treeHandle.acquire();
            }
            return this.treeHandle;
        }
        return this.treeHandle.acquire();
    }


    /**
     * @param context