libssh2_channel_write_ex: remove macros, added wording on buffer size

docs/libssh2_channel_write_ex.3

@@ -4,16 +4,12 @@
 .SH NAME
 libssh2_channel_write_ex - write data to a channel stream blocking
 .SH SYNOPSIS
+.nf
 #include <libssh2.h>
 
-ssize_t
-libssh2_channel_write_ex(LIBSSH2_CHANNEL *channel, int stream_id, char *buf, size_t buflen);
-
-ssize_t
-libssh2_channel_write(LIBSSH2_CHANNEL *channel, char *buf, size_t buflen);
-
-ssize_t
-libssh2_channel_write_stderr(LIBSSH2_CHANNEL *channel, char *buf, size_t buflen);
+ssize_t libssh2_channel_write_ex(LIBSSH2_CHANNEL *channel,
+                                 int stream_id, char *buf,
+                                 size_t buflen);
 .SH DESCRIPTION
 Write data to a channel stream. All channel streams have one standard I/O
 substream (stream_id == 0), and may have up to 2^32 extended data streams as
@@ -29,7 +25,12 @@ defines a stream ID of 1 to be the stderr substream.
 \fIbuflen\fP - size of the data to write
 
 \fIlibssh2_channel_write(3)\fP and \fIlibssh2_channel_write_stderr(3)\fP are
-macros.
+convenience macros for this function.
+
+\fIlibssh2_channel_write_ex(3)\fP will use as much as possible of the buffer
+and put it into a single SSH protocol packet. This means that to get maximum
+performance when sending larger files, you should try to always pass in at
+least 32K of data to this function.
 .SH RETURN VALUE
 Actual number of bytes written or negative on failure.
 LIBSSH2_ERROR_EAGAIN when it would otherwise block. While